Compositions for Treating Pathological Calcification Conditions, and Methods Using Same

ABSTRACT

The present invention includes compositions and methods for treating diseases or disorders associated with pathological calcification or pathological ossification. In certain embodiments, the diseases or disorders are selected from the group consisting of Generalized Arterial Calcification of Infancy (GACI), Idiopathic Infantile Arterial Calcification (IIAC), Ossification of the Posterior Longitudinal Ligament (OPLL), hypophosphatemic rickets, osteoarthritis, calcification of atherosclerotic plaques, PXE, hereditary and non-hereditary forms of osteoarthritis, ankylosing spondylitis, hardening of the arteries occurring with aging, calciphylaxis resulting from end stage renal disease and progeria.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of, and claims priority to,U.S. patent application Ser. No. 16/728,129, filed Dec. 27, 2019, nowallowed, which is a continuation of U.S. application Ser. No.16/380,557, filed Apr. 10, 2019, now U.S. Pat. No. 10,517,927, which isa continuation of U.S. patent application Ser. No. 15/812,456, filedNov. 14, 2017, now U.S. Pat. No. 10,960,049, which is a continuation of,and claims priority to, PCT International Application No.PCT/US2016/033236, filed May 19, 2016, which claims priority under 35U.S.C. § 119(e) to U.S. Provisional Patent Application No. 1062/163,500, filed May 19, 2015, all of which applications areincorporated herein by reference in their entireties.

BACKGROUND OF THE INVENTION

Generalized arterial calcification of infancy (GACI) is an ultra-rareneonatal disease characterized by infantile onset of widespread arterialcalcifications in large and medium sized vessels resulting incardiovascular collapse and death in the neonatal period. The diseasepresents clinically with heart failure, respiratory distress,hypertension, cyanosis, and cardiomegaly. The prognosis is grave, witholder reports of a mortality rate of 85% at six months, while recentlyintensive treatment with bisphosphonates has lowered mortality to 55% atsix months. Tempering this apparent progress is the severe skeletaltoxicity associated with prolonged use of etridonate in patients withGACI, the observation that the limited available data makes it difficultto determine if bisphosphonate treatment is truly protective or reflectsthe natural history of the disease in less effected patients, and theineffectiveness of bisphosphonates to prevent mortality in some patientseven when instituted early.

The overall incidence of GACI is rare, with 200 reported cases in themedical literature and a disease frequency of one in 391,000. Althoughthe disease was first described by Bryant and White in 1901, it was notuntil 2000 that Rutsch and colleagues noted that serum PPi levels andENPP1 enzymatic activity was significantly impaired in GACI patients.ENPP1 (also known as NPP1 or PC-1) is a member of the ectonucleotidepyrophosphatase/phosphodiesterase (also known as ENPP or NPP) family ofenzymes, which are characterized by phosphodiesterase activity, and is atype II extracellular membrane bound glycoprotein located on themineral-depositing matrix vesicles of osteoblasts and chondrocytes, aswell as the vascular surface of cerebral capillaries. ENPP1 catabolizesthe degradation of extracellular ATP into AMP and PPi. PPi inhibitsectopic tissue mineralization, presumably by occupying some of the Pisites on the surface of nascent or growing hydroxyapatite (HA) crystals,thereby creating irregularities that slow or terminate the propagationof crystal growth. Inactivating mutations in ENPP1 account for 75% ofGACI patients, and a sizable fraction of the remaining patients resultfrom inactivating mutations in the ATP dependent membrane transporterMRP6, encoded by the abcc6 gene. Mutations in abcc6 have been linked todecreased extracellular concentrations of nucleoside triphosphates,thereby limiting ENPP1's metabolism of ATP into extracellular PPi.

Kidneys are integral to maintenance of normal bone and mineralmetabolism, including excretion of phosphate. Patients with kidneyfailure are unable to appropriately regulate serum mineral balance andtend to retain phosphate that is absorbed from the various dietarycomponents. A high serum level of phosphate is associated with excessivesecretion of parathyroid hormone and a tendency to calcification of thesoft tissues including the blood vessels.

In patients with kidney failure, excess removal of phosphate andpyrophosphate anions can occur during hemodialysis or peritonealdialysis. Depletion of these anions from tissues and plasma leads todisorders of bone and mineral metabolism, including osteomalacia andcalcification of soft tissues and bone disease. Pyrophosphate deficiencymay be a risk factor for deposition of calcium into the small vessels ofthe skin, causing an inflammatory vasculitis called calciphylaxis thatcan lead to gangrene of the skin and underlying tissues, resulting insevere, chronic pain. Calciphylaxis may necessitate amputation of theaffected limb and is commonly fatal, with no effective treatment forthis condition. Ectopic calcification, if left untreated, results inincreased morbidity and death. It is important to regulate the amount ofpyrophosphate in the system and reduce the occurrence of calciphylaxisin patients.

In 2003, 19.5 million U.S. adults have chronic kidney disease (CKD), and13.6 million had stage 2-5 CKD, as defined by the National KidneyFoundation Kidney Disease Outcomes Quality Initiative (NKFK/DOQI).Adverse outcomes of chronic kidney disease can often be prevented ordelayed through early detection and treatment.

The prevalence of end-stage renal disease (ESRD) is increasing at analarming rate. In 2000, end stage kidney disease developed in over90,000 people in the U.S. The population of patients on dialysis therapyor needing transplantation was 380,000 in 2003, and became 651,000patients in 2010. Care for patients with ESRD already consumes more than$18 billion per year in the U.S., a substantial burden for the healthcare system.

Calcific uremic arteriolopathy (also known as CUA) is a fatal diseaseseen in patients with chronic kidney disease (CKD) on dialysis.Calcification of small arteries leads to ischemia of the tissue andskin, infarction and thrombosis, with patient mortality close to 80%.Currently there are 450,000 patients on dialysis in the U.S. who are atrisk of acquiring CUA, and there is no FDA approved treatments for thedisease. CUA has hallmarks resembling GACI and other disorders ofcalcification with exhibiting low levels of PPi and high levels offibroblast growth factor 23 (or FGF23). In ESRD patients requiringdialysis, this calcification process is further accelerated, with anaverage life-expectancy of 5-6 years.

Pseudoxanthoma elasticum (PXE) is a heritable disorder characterized bymineralization of elastic fibers in skin, arteries and the retina, thatresult in dermal lesions with associated laxity and loss of elasticity,arterial insufficiency, cardiovascular disease and retinal hemorrhagesleading to macular degeneration. Mutations associated with PXE are alsolocated in the abcc6 gene. The skin manifestations are among the mostcommon characteristics of PXE, but the ocular and cardiovascularsymptoms are responsible for the morbidity of the disease.Characteristic skin lesions (yellowish papules and plaques and laxitywith loss of elasticity, typically seen on the face, neck, axilla,antecubital fossa, popliteal fossa, groin and periumbilical areas) aregenerally an early sign of PXE and result from an accumulation ofabnormal mineralized elastic fibers in the mid-dermis and. They areusually detected during childhood or adolescence and progress slowly andoften unpredictably. A PXE diagnosis can be confirmed by a skin biopsythat shows calcification of fragmented elastic fibers in the mid- andlower dermis.

Common cardiovascular complications of PXE are due to the presence ofabnormal calcified elastic fibers in the internal elastic lamina ofmedium-sized arteries. The broad spectrum of phenotypes includespremature atherosclerotic changes, intimal fibroplasia causing angina orintermittent claudication or both, early myocardial infarction andhypertension. Fibrous thickening of the endocardium and atrioventricularvalves can also result in restrictive cardiomyopathy. Approximately 10%of PXE patients also develop gastrointestinal bleeding and centralnervous system complications (such as stroke and dementia) as aconsequence of systemic arterial wall mineralization. In addition,renovascular hypertension and atrial septal aneurysm can be seen in PXEpatients.

Conditions in which serum phosphate levels are reduced or elevated arereferred to as hypophosphatemia and hyperphosphatemia, respectively.Hypophosphatemia, which often results from renal phosphate wasting, iscaused by a number of genetic disorders including X-linkedhypophosphatemic rickets (XLH), hereditary hypophosphatemic rickets withhypercalciuria (HHRH), hypophosphatemic bone disease (HBD), andautosomal dominant hypopohsphatemic rickets (ADHR). The exact molecularmechanisms by which proper serum phosphate concentrations are maintainedare poorly understood, but it is crucial to maintain serum phosphatelevels in order to alleviate symptoms of aforesaid diseases.

There is thus a need in the art for novel compositions and methods fortreating diseases and disorders associated with pathologicalcalcification and/or pathological ossification. Such compositions andmethods should not undesirably disturb other physiologic processes. Thepresent invention fulfills this need.

BRIEF SUMMARY OF THE INVENTION

The invention provides a compound of formula (I), or a salt or solvatethereof. The invention further provides a method of treating orpreventing a disease or disorder associated with pathologicalcalcification or pathological ossification in a subject in need thereof.The invention further provides a method of reducing or preventingcardiac calcifications, arterial calcifications and/or elastic fibermineralizations in an infant afflicted with at least one disease ordisorder selected from the group consisting of GACI and PXE.

In certain embodiments, the compound of formula (I) isPROTEIN-Z-DOMAIN-X-Y (I), wherein in (I): PROTEIN is selected from thegroup consisting of SEQ ID NO:15, SEQ ID NO:17, SEQ ID NO:19, and SEQ IDNO:24; DOMAIN is selected from the group consisting of a human IgG Fcdomain (also referred to as Fc), human serum albumin protein (alsoreferred to as ALB) and fragment thereof; X and Z are independentlyabsent or a polypeptide comprising 1-20 amino acids; and, Y is absent oris a sequence selected from the group consisting of: (DSS)_(n) (SEQ IDNO:4), (ESS)_(n) (SEQ ID NO:5), (RQQ)_(n) (SEQ ID NO:6), (KR)_(n) (SEQID NO:7), R_(m) (SEQ ID NO:8), DSSSEEKFLRRIGRFG (SEQ ID NO:9),EEEEEEEPRGDT (SEQ ID NO:10), APWHLSSQYSRT (SEQ ID NO:11), STLPIPHEFSRE(SEQ ID NO:12), VTKHLNQISQSY (SEQ ID NO:13), and E_(m) (SEQ ID NO:14),wherein m is an integer ranging from 1 to 15, and wherein n is aninteger ranging from 1 to 10.

In certain embodiments, DOMAIN is a Fc or fragment thereof. In otherembodiments, DOMAIN is an ALB or fragment thereof.

In certain embodiments, Y is absent and the compound lacks anegatively-charged bone-targeting sequence.

In certain embodiments, the PROTEIN has a mutation in at least oneposition selected from the group consisting of Ser 532, Tyr 529, Tyr451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relativeto SEQ ID NO:1. In other embodiments, the nuclease domain of the PROTEINor mutant thereof is absent. In yet other embodiments, the nucleasedomain from about residue 524 to about residue 885 relative to SEQ IDNO:1 is absent in the PROTEIN or mutant thereof. In yet otherembodiments, a segment of the extracellular region of NNP2 containing afurin or signal peptide cleavage site is, or is not, substituted intothe PROTEIN or mutant thereof.

In certain embodiments, DOMAIN is a Fc or fragment thereof, and whereinPROTEIN-Z-DOMAIN comprises (SEQ ID NO:15)-Z-(Fc or fragment thereof),(SEQ ID NO:17)-Z-(Fc or fragment thereof), (SEQ ID NO:19)-Z-(Fc orfragment thereof), (SEQ ID NO:24)-Z-(Fc or fragment thereof), or amutant thereof comprising at least one mutation in at least one positionselected from the group consisting of Ser 532, Tyr 529, Tyr 451, Ile450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relative to SEQ IDNO:1.

In certain embodiments, PROTEIN-Z-DOMAIN comprises SEQ ID NO:16, SEQ IDNO:18, SEQ ID NO:20, (SEQ ID NO:24)-Z-(SEQ ID NO:26), or a mutantthereof comprising at least one mutation in at least one positionselected from the group consisting of Ser 532, Tyr 529, Tyr 451, Ile450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relative to SEQ IDNO:1.

In certain embodiments, DOMAIN is an ALB or fragment thereof, andwherein PROTEIN-Z-DOMAIN comprises (SEQ ID NO:15)-Z-(ALB or fragmentthereof), (SEQ ID NO:17)-Z-(ALB or fragment thereof), (SEQ IDNO:19)-Z-(ALB or fragment thereof), (SEQ ID NO:24)-Z-(ALB or fragmentthereof), or a mutant thereof comprising at least one mutation in atleast one position selected from the group consisting of Ser 532, Tyr529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser289, Ser 287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536,relative to SEQ ID NO:1.

In certain embodiments, PROTEIN-Z-DOMAIN comprises SEQ ID NO:21, (SEQ IDN:17)-Z-(SEQ ID NO:27), SEQ ID NO:22, SEQ ID NO:25, or a mutant thereofcomprising at least one mutation in at least one position selected fromthe group consisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser525, Gly 342, Ser 343 and Gly 536, relative to SEQ ID NO:1.

In certain embodiments, the compound has a k_(cat) value greater than orequal to about 3.4 (±0.4) s⁻¹ enzyme⁻¹, wherein the k_(cat) isdetermined by measuring the compound's ATP hydrolysis rate.

In certain embodiments, the compound has a K_(M) value less than orequal to about 2 μM, wherein the K_(M) is determined by measuring thecompound's ATP hydrolysis rate.

In certain embodiments, the NPP1 polypeptide is a cleavage product of aprecursor NPP1 polypeptide comprising an ecto-nucleotidepyrophosphate/phosphodiesterase-2 (NPP2) transmembrane domain.

In certain embodiments, the NPP2 transmembrane domain is residues 12-30of NCBI accession no. NP_001124335 (SEQ ID NO:2), which corresponds toSEQ ID NO:23.

In certain embodiments, the method comprises administering to thesubject a therapeutically effective amount of at least one compound ofthe invention.

In certain embodiments, the disease comprises at least one selected fromthe group consisting of Generalized Arterial Calcification of Infancy(GACI), Idiopathic Infantile Arterial Calcification (IIAC), Ossificationof the Posterior Longitudinal Ligament (OPLL), hypophosphatemic rickets,osteoarthritis, and calcification of atherosclerotic plaques.

In certain embodiments, the disease comprises at least one selected fromthe group consisting of PXE, hereditary and non-hereditary forms ofosteoarthritis, ankylosing spondylitis, hardening of the arteriesoccurring with aging, calciphylaxis resulting from end stage renaldisease and progeria.

In certain embodiments, Y is absent and the compound lacks anegatively-charged bone-targeting sequence.

In certain embodiments, the method comprises administering to the infanta therapeutically effective amount of a given polypeptide comprising anecto-nucleotide pyrophosphate/phosphodiesterase-1 (NPP1) polypeptide andan IgG Fc domain, wherein the given polypeptide lacks a polyasparticacid domain, whereby the administering of the given polypeptideincreases extracellular pyrophosphate (PPi) concentrations in theinfant.

In certain embodiments, the method comprises administering to the infanta therapeutically effective amount of a given polypeptide comprising anecto-nucleotide pyrophosphate/phosphodiesterase-1 (NPP1) polypeptide andan ALB, wherein the given polypeptide lacks a polyaspartic acid domain,whereby the administering of the given polypeptide increasesextracellular pyrophosphate (PPi) concentrations in the infant.

In certain embodiments, the administering is at least one selected fromthe group consisting of inhalational, oral, nasal, rectal, parenteral,sublingual, transdermal, transmucosal (e.g., sublingual, lingual,(trans)buccal, (trans)urethral, vaginal (e.g., trans- andperivaginally), (intra)nasal, and (trans)rectal), intravesical,intrapulmonary, intraduodenal, intragastrical, intrathecal,subcutaneous, intramuscular, intradermal, intra-arterial, intravenous,intrabronchial, inhalation, and topical. In other embodiments, theadministering is subcutaneous.

In certain embodiments, the administering restores the infant'sextracellular pyrophosphate concentrations to a level within the rangefound in an infant not afflicted with GACI and/or PXE.

In certain embodiments, the infant presents and/or is diagnosed with“failure to thrive” prior to the administering.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of illustrative embodiments of theinvention will be better understood when read in conjunction with theappended drawings. For the purpose of illustrating the invention, thereare shown in the drawings specific embodiments. It should be understood,however, that the invention is not limited to the precise arrangementsand instrumentalities of the embodiments shown in the drawings.

FIGS. 1A-1G comprise a set of images and graphs illustrating a naturalhistory study. FIG. 1A: Average daily weights of ENPP1-asj/asj andENPP1-WT sibling pairs on acceleration diet. Daily weights of ENPP1-WT(Cyan squares) and ENPP1-asj/asj mice (Green circles) on theacceleration diet over a 70 day period. A failure to thrive point isnoted in the ENPP1-asj/asj cohort at day 26, when the weights divergefrom ENPP1-WT. Death events are marked with red arrows. FIG. 1B:Survival Curves, Natural History Study. Mean survival of ENPP1-asj/asjwas 58 days. No deaths were observed in the ENPP1-WT cohort. FIG. 1C:Representative Micro-CT and histology, Natural History Study. Someasj/asj animals displayed dramatic calcifications in heart and aortavisible on E). Aortas of ENPP1-asj/asj mouse all possessed nearcircumferential calcifications that were pervasive in the vascularwalls, as illustrated by Alzarian red staining of the aortas. FIG. 1F:Histology of asj/asj mice, Left Ventricle (40×). Extensivecalcifications surrounded by scar tissue revealing the presence ofrepeated, old, healed myocardial infarctions. FIG. 1G: Histology ofasj/asj mice, Septum (100×). More typically, the asj mice displayedsmall foci of calcifications with surrounding scar tissue as seen herein the myocardial septum, also diagnostic of previous myocardialinfarctions.

FIGS. 2A-2E comprise a set of images and graphs illustrating a metabolicpathway, as well as design, stability, and kinetic properties of atherapeutic protein of the invention. FIG. 2A: Schematic of themetabolic pathway of purinergic metabolism related to ectopiccalcification. ENPP1 converts extracellular ATP into AMP and PPi, TNAPconverts PPi into Pi, and CD73 converts AMP into adenosine and Pi. Theabcc6 gene encodes MRP6, a membrane transporter that increases theextracellular concentration of ATP. Loss of function mutations in TNAPresult in familial hypophosphatasia. Loss of function mutations in ENPP1result in GACI, loss of function mutations in MRP6 result in PXE, andloss of function mutations in CD73 results in a disease of arterial andjoint calcification termed ‘ACDC’. FIG. 2B: Design of ENPP1 proteintherapeutic. To produce a soluble recombinant protein, a segment of theextracellular region of NPP2 containing a furin cleavage site wassubstituted into ENPP1 as previously described, and the protein wasC-terminally fused with the Fc domain of human immunoglobulin 1 (IgG1).FIG. 2C: Stability of ENPP1 therapeutic. ENPP1-Fc Ap3A activity was seento be stable to freeze-thaw cycle in PBS following storage at −80° C.FIGS. 2D-2E: Steady state kinetics of hENPP1-Fc. FIG. 2D: Time coursesof AMP formation measured by HPLC analysis after addition of 10 nMhNPP1-Fc to (from bottom to top) 1.0, 2.0, 7.8, 125 and 250 μM ATP. Thesmooth curves though data are fits obtained by non-linear kinetic timecourse analysis. The insert shows the lower [ATP] time courses in PanelA, (from bottom to top) 1.0, 2.0, 7.8 μM ATP. The time course of 1.0 μMATP shows the ATP was depleted completely after 1 min and therefore therate was not able to be determined. FIG. 2E: ATP concentration dependentinitial ATP hydrolysis rate per enzyme. The initial rates after 7.8 μMare essentially the same with k_(cat) (the average)=3.4 (±0.4) s⁻¹enzyme⁻¹. The initial rate at 2.0 μM ATP concentration is about a halfof k_(cat) value, and therefore K_(M)˜2 μM is estimated for ATPhydrolysis by hNPP1-Fc protein.

FIGS. 3A-3D comprise a set of images and graphs illustrating a proof ofconcept study. FIG. 3A: Daily animal weights. Average daily weights ofENPP1-WT and ENPP1-asj/asj sibling pairs dosed with vehicle (daily PBSinjections supplemented with weekly GK 1.5) compared to ENPP1-asj/asjsibling pairs dosed with daily with mouse ENPP1-Fc (mENPPI-Fc)@500 au/KgqD in PBS and weekly GK1.5 immunosuppression. Dosing and weighingcommenced on day 14. Deaths in the ENPP1-asj/asj+vehicle cohort aredenoted by red arrows on the day of death. No deaths were noted in theENPP1-WT+vehicle or ENPP1-asj/asj+ENPP1-Fc cohort. FIG. 3B: SurvivalCurves, Proof of Concept Study. FIG. 3C: Left ventricle histology, (40×,H&E), untreated asj/asj mouse displaying large focus of calcificationsand micro-infarctions in the free wall. FIG. 3D: Left ventriclehistology, (40×, H&E), treated asj/asj mouse. None of the treatedENPP1-asj mice displayed abnormal Left Ventricular Histology.

FIGS. 4A-4G comprise a set of images illustrating representativehistology and a proof of concept study. FIGS. 4A-4B: Aorta (40×,alzarian red). Untreated ENPP1-asj mice (FIG. 4A) displayed nearlycircumferential aortic calcifications, while treated ENPP1-asj mice(FIG. 4B) did not. FIG. 4C: Untreated ENPP1-asj/asj mice, RightVentricle (40×, H&E). Two untreated ENPP1-asj mice had large, confluent,myocardial infarctions in the free wall of the Right Ventricle. FIG. 4D:Treated ENPP1-asj/asj mice, Right Ventricle (40×, H&E). All treatedENPP1-asj mice displayed normal Right. ventricle myocardium. FIG. 4E:Untreated ENPP1-asj/asj mice, Coronary Arteries (100×, H&E). Alluntreated ENPP1-asj/asj mice had coronary calcifications, with mostdisplaying circumferential calcifications in coronary arteriessurrounded by scar tissue, diagnostic of ischemia and myocardialinfarction. FIG. 4F: Untreated ENPP1-asj/asj mice, Myocardial Septum(100×, H&E). Nearly all animals (77%) displayed intracardiaccalcifications surrounded by scar tissue, as demonstrated in this animalin the myocardial septum. FIG. 4G: Phenotypic comparison, treated anduntreated ENPP1-asj/asj mice. There is a dramatic size difference in thetreated and untreated animals, and a marked difference in the mobilityand health of the animals, best seen in the movie submitted in thesupplemental data.

FIGS. 5A-5F comprise a set of images and graphs illustrating biomarkersof disease response. FIG. 5A: Postmortem high-resolution micro-CT scansrevealed extensive calcifications in untreated ENPP1-asj/asj mice in thehearts, coronary arteries, and ascending and descending aortas, butabsolutely no calcifications in these organs in the treatedENPP1-asj/asj cohort or in ENPP1-WT mice. FIG. 5B: Plasma [PPi] inENPP1-WT and treated and untreated ENPP1-asj/asj animals revealed thattreatment with ENPP1-FC increased [PPi] in ENPP1-asj/asj mice above WTlevels, and well above the nearly undetectable levels present inuntreated ENPP1-asj/asj mice. FIGS. 5C-5D: Percent uptake of injected^(99m)PYP in heads of WT and asj/asj animals. The % uptake of ^(99m)PYPin heads of animals in the natural history study were recorded weekly inthe WT and asj/asj animals on the acceleration diet, demonstrating that^(99m)PYP uptake remains nearly constant over an 80 day period followingbirth, but differs markedly between the two experimental groups. FIG.5D: In the natural history study, the average ^(99m)PYP uptake in headsof WT animals was around 15% of injected dose over the 80 day period,while the PYP uptake in asj/asj animals was around 20% (p<0.001,students 2-tailed T-test). FIGS. 5E-5F: Percent ^(99m)PYP uptake ofinjected dose in the heads of WT, and treated and untreated asj/asjmice. ^(99m)PYP uptake was recorded in the middle of the study (day30-35, (FIG. 5e )) and at the end of the study (day 50-65, FIG. 5F) inthe experimental groups. WT and treated asj/asj animals had percentuptake in the skulls around 15%, while the untreated ENPP1-asj/asjcohort was at or above 20%. The difference between treated and untreatedENPP1-asj mice was statistically significant (p<0.001, students 2-tailedT-test), while the difference between WT and treated ENPP1-asj mice wasnot.

FIG. 6, comprising panels a-h, illustrates certain non-limitingconstructs of NPP1 fusion proteins. X and Y are optional peptides insome embodiments. Z is an optional linker that connects either Fc domainor HSA domain to the C terminus of NPP1 protein. The N and C terminalregions of NPP1 protein are depicted as N and C in FIG. 6. Panels a-dillustrate fusion proteins comprising transmembrane domain of NPP2(marked as ‘*’) and NPP1 (marked as ‘**’) along with NPP1 enzymaticdomain. The enzymatic domain of NPP1 begins as PSCAKE amino acidsequence and ends at QED amino acid sequence. Panels e-h illustratefusion proteins comprising signal peptide of NPP2 (marked as ‘*’) andtransmembrane domain of NPP1 (marked as ‘**’) along with NPP1 enzymaticdomain.

FIG. 7 is a graph illustrating measured plasma PPi levels in micetreated with ENPP1-Fc as described in Example 1.

FIG. 8 is a schematic illustration of a plasmid used to express SEQ IDNO:22.

FIG. 9 is a schematic illustration of a plasmid used to express SEQ IDNO:25.

FIG. 10 is an image illustrating a silver staining image from purifiedhuman and mouse NPP1-Fc constructs.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the discovery that certainNPP1-containing polypeptides, mutants, or mutant fragments thereof, areuseful for the treatment of diseases and disorders involving plasmapyrophosphate imbalance, pathological calcification and/or pathologicalossification. Diseases and disorders involving pathologicalcalcification and/or pathological ossification treatable by thecompositions and methods of the invention, include, but are not limitedto Generalized Arterial Calcification of Infancy (GACI), Chronic KidneyDisease (CKD), End Stage Renal Disease (ESRD), Idiopathic InfantileArterial Calcification (IIAC), Ossification of the PosteriorLongitudinal Ligament (OPLL), hypophosphatemic rickets, calcification ofatherosclerotic plaques, Pseudoxanthoma elasticum (PXE), hereditary andnon-hereditary forms of osteoarthritis, ankylosing spondylitis,hardening of the arteries occurring with aging, calciphylaxis (such asresulting from end stage renal disease) and progeria.

Such diseases are a result of myriad causes: some are genetic mutationsand some are complication as a result of diabetes, heart failure orextensive dialysis. Yet, in certain embodiments, they share in commonthe symptom of plasma pyrophosphate imbalance and/or extensivecalcification.

Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the present invention, illustrative methodsand materials are described.

As used herein, each of the following terms has the meaning associatedwith it in this section.

The articles “a” and “an” are used herein to refer to one or to morethan one (i.e., to at least one) of the grammatical object of thearticle. By way of example, “an element” means one element or more thanone element.

“About” as used herein when referring to a measurable value such as anamount, a temporal duration, and the like, is meant to encompassvariations of ±20% or ±10%, in certain embodiments ±5%, in certainembodiments ±1%, in certain embodiments ±0.1% from the specified value,as such variations are appropriate to perform the disclosed methods.

The term “abnormal” when used in the context of organisms, tissues,cells or components thereof, refers to those organisms, tissues, cellsor components thereof that differ in at least one observable ordetectable characteristic (e.g., age, treatment, time of day, etc.) fromthose organisms, tissues, cells or components thereof that display the“normal” (expected) respective characteristic. Characteristics which arenormal or expected for one cell or tissue type, might be abnormal for adifferent cell or tissue type.

As used herein, the term “ALB” refers to a human serum albumin protein.

A disease or disorder is “alleviated” if the severity of a symptom ofthe disease or disorder, the frequency with which such a symptom isexperienced by a patient, or both, is reduced.

As used herein the terms “alteration,” “defect,” “variation” or“mutation” refer to a mutation in a gene in a cell that affects thefunction, activity, expression (transcription or translation) orconformation of the polypeptide it encodes. Mutations encompassed by thepresent invention can be any mutation of a gene in a cell that resultsin the enhancement or disruption of the function, activity, expressionor conformation of the encoded polypeptide, including the completeabsence of expression of the encoded protein and can include, forexample, missense and nonsense mutations, insertions, deletions,frameshifts and premature terminations. Without being so limited,mutations encompassed by the present invention may alter splicing themRNA (splice site mutation) or cause a shift in the reading frame(frameshift).

The term “amino acid sequence variant” refers to polypeptides havingamino acid sequences that differ to some extent from a native sequencepolypeptide. Ordinarily, amino acid sequence variants possess at leastabout 70% homology, at least about 80% homology, at least about 90%homology, or at least about 95% homology to the native polypeptide. Theamino acid sequence variants possess substitutions, deletions, and/orinsertions at certain positions within the amino acid sequence of thenative amino acid sequence.

The term “antibody,” as used herein, refers to an immunoglobulinmolecule which is able to specifically bind to a specific epitope on anantigen. Antibodies can be intact immunoglobulins derived from naturalsources or from recombinant sources and can be immunoreactive portionsof intact immunoglobulins. The antibodies in the present invention mayexist in a variety of forms including, for example, polyclonalantibodies, monoclonal antibodies, intracellular antibodies(“intrabodies”), Fv, Fab and F(ab)2, as well as single chain antibodies(scFv), heavy chain antibodies, such as camelid antibodies, syntheticantibodies, chimeric antibodies, and a humanized antibodies (Harlow, etal., 1999, Using Antibodies: A Laboratory Manual, Cold Spring HarborLaboratory Press, NY; Harlow, et al., 1989, Antibodies: A LaboratoryManual, Cold Spring Harbor, N.Y.; Houston, et al., 1988, Proc. Natl.Acad. Sci. USA 85:5879-5883; Bird, et al., 1988, Science 242:423-426).

As used herein, the term “Ap3P” refers toadenosine-(5′)-triphospho-(5′)-adenosine or a salt thereof.

As used herein, the terms “child” and “infant” are used interchangeably.

The term “coding sequence,” as used herein, means a sequence of anucleic acid or its complement, or a part thereof, that can betranscribed and/or translated to produce the mRNA and/or the polypeptideor a fragment thereof. Coding sequences include exons in a genomic DNAor immature primary RNA transcripts, which are joined together by thecell's biochemical machinery to provide a mature mRNA. The anti-sensestrand is the complement of such a nucleic acid, and the coding sequencecan be deduced therefrom. In contrast, the term “non-coding sequence,”as used herein, means a sequence of a nucleic acid or its complement, ora part thereof, that is not translated into amino acid in vivo, or wheretRNA does not interact to place or attempt to place an amino acid.Non-coding sequences include both intron sequences in genomic DNA orimmature primary RNA transcripts, and gene-associated sequences such aspromoters, enhancers, silencers, and the like.

As used herein, the terms “complementary” or “complementarity” are usedin reference to polynucleotides (i.e., a sequence of nucleotides)related by the base-pairing rules. For example, the sequence “A-G-T,” iscomplementary to the sequence “T-C-A.” Complementarity may be “partial,”in which only some of the nucleic acids' bases are matched according tothe base pairing rules. Or, there may be “complete” or “total”complementarity between the nucleic acids. The degree of complementaritybetween nucleic acid strands has significant effects on the efficiencyand strength of hybridization between nucleic acid strands. This is ofparticular importance in amplification reactions, as well as detectionmethods that depend upon binding between nucleic acids.

As used herein, the terms “conservative variation” or “conservativesubstitution” as used herein refers to the replacement of an amino acidresidue by another, biologically similar residue. Conservativevariations or substitutions are not likely to change the shape of thepeptide chain. Examples of conservative variations, or substitutions,include the replacement of one hydrophobic residue such as isoleucine,valine, leucine or methionine for another, or the substitution of onepolar residue for another, such as the substitution of arginine forlysine, glutamic for aspartic acid, or glutamine for asparagine.

A “disease” is a state of health of an animal wherein the animal cannotmaintain homeostasis, and wherein if the disease is not ameliorated thenthe animal's health continues to deteriorate.

A “disorder” in an animal is a state of health in which the animal isable to maintain homeostasis, but in which the animal's state of healthis less favorable than it would be in the absence of the disorder. Leftuntreated, a disorder does not necessarily cause a further decrease inthe animal's state of health.

As used herein, the term “domain” refers to a part of a molecule orstructure that shares common physicochemical features, such as, but notlimited to, hydrophobic, polar, globular and helical domains orproperties. Specific examples of binding domains include, but are notlimited to, DNA binding domains and ATP binding domains.

As used herein, the terms “effective amount,” “pharmaceuticallyeffective amount” and “therapeutically effective amount” refer to anontoxic but sufficient amount of an agent to provide the desiredbiological result. That result may be reduction and/or alleviation ofthe signs, symptoms, or causes of a disease, or any other desiredalteration of a biological system. An appropriate therapeutic amount inany individual case may be determined by one of ordinary skill in theart using routine experimentation.

“Encoding” refers to the inherent property of specific sequences ofnucleotides in a polynucleotide, such as a gene, a cDNA, or an mRNA, toserve as templates for synthesis of other polymers and macromolecules inbiological processes having either a defined sequence of nucleotides(i.e., rRNA, tRNA and mRNA) or a defined sequence of amino acids and thebiological properties resulting therefrom. Thus, a gene encodes aprotein if transcription and translation of mRNA corresponding to thatgene produces the protein in a cell or other biological system. Both thecoding strand, the nucleotide sequence of which is identical to the mRNAsequence and is usually provided in sequence listings, and thenon-coding strand, used as the template for transcription of a gene orcDNA, can be referred to as encoding the protein or other product ofthat gene or cDNA.

As used herein, the term “Fc” refers to a human IgG Fc domain.

As used herein, the term “failure to thrive” refers to a child or infantwhose current weight or rate of weight gain is lower than that of otherchildren of similar age and gender. The situation where a child orinfant “fails to thrive” can be identified by consultation with amedical specialist, and/or comparison of the child's or infant's weightor weight gain rate with known average age-specific weight or weightgain rate data.

As used herein, the term “fragment,” as applied to a nucleic acid,refers to a subsequence of a larger nucleic acid. A “fragment” of anucleic acid can be at least about 15 nucleotides in length; forexample, at least about 50 nucleotides to about 100 nucleotides; atleast about 100 to about 500 nucleotides, at least about 500 to about1000 nucleotides; at least about 1000 nucleotides to about 1500nucleotides; about 1500 nucleotides to about 2500 nucleotides; or about2500 nucleotides (and any integer value in between). As used herein, theterm “fragment,” as applied to a protein or peptide, refers to asubsequence of a larger protein or peptide. A “fragment” of a protein orpeptide can be at least about 20 amino acids in length; for example, atleast about 50 amino acids in length; at least about 100 amino acids inlength; at least about 200 amino acids in length; at least about 300amino acids in length; or at least about 400 amino acids in length (andany integer value in between).

“Homologous” refers to the sequence similarity or sequence identitybetween two polypeptides or between two nucleic acid molecules. When aposition in both of the two compared sequences is occupied by the samebase or amino acid monomer subunit, e.g., if a position in each of twoDNA molecules is occupied by adenine, then the molecules are homologousat that position. The percent of homology between two sequences is afunction of the number of matching or homologous positions shared by thetwo sequences divided by the number of positions compared X 100. Forexample, if 6 of 10 of the positions in two sequences are matched orhomologous then the two sequences are 60% homologous. By way of example,the DNA sequences ATTGCC and TATGGC share 50% homology. Generally, acomparison is made when two sequences are aligned to give maximumhomology.

As used herein, an “immunoassay” refers to any binding assay that usesan antibody capable of binding specifically to a target molecule todetect and quantify the target molecule.

The term “immunoglobulin” or “Ig,” as used herein is defined as a classof proteins, which function as antibodies. Antibodies expressed by Bcells are sometimes referred to as the BCR (B cell receptor) or antigenreceptor. The five members included in this class of proteins are IgA,IgG, IgM, IgD, and IgE. IgA is the primary antibody that is present inbody secretions, such as saliva, tears, breast milk, gastrointestinalsecretions and mucus secretions of the respiratory and genitourinarytracts. IgG is the most common circulating antibody. IgM is the mainimmunoglobulin produced in the primary immune response in most subjects.It is the most efficient immunoglobulin in agglutination, complementfixation, and other antibody responses, and is important in defenseagainst bacteria and viruses. IgD is the immunoglobulin that has noknown antibody function, but may serve as an antigen receptor. IgE isthe immunoglobulin that mediates immediate hypersensitivity by causingrelease of mediators from mast cells and basophils upon exposure toallergen.

“Instructional material,” as that term is used herein, includes apublication, a recording, a diagram, or any other medium of expressionwhich can be used to communicate the usefulness of the nucleic acid,peptide, and/or compound of the invention in the kit for identifying oralleviating or treating the various diseases or disorders recitedherein. Optionally, or alternately, the instructional material maydescribe one or more methods of identifying or alleviating the diseasesor disorders in a cell or a tissue of a subject. The instructionalmaterial of the kit may, for example, be affixed to a container thatcontains the nucleic acid, polypeptide, and/or compound of the inventionor be shipped together with a container that contains the nucleic acid,polypeptide, and/or compound. Alternatively, the instructional materialmay be shipped separately from the container with the intention that therecipient uses the instructional material and the compoundcooperatively.

“Isolated” means altered or removed from the natural state. For example,a nucleic acid or a polypeptide naturally present in a living animal isnot “isolated,” but the same nucleic acid or polypeptide partially orcompletely separated from the coexisting materials of its natural stateis “isolated.” An isolated nucleic acid or protein can exist insubstantially purified form, or can exist in a non-native environmentsuch as, for example, a host cell.

An “isolated nucleic acid” refers to a nucleic acid segment or fragmentwhich has been separated from sequences which flank it in a naturallyoccurring state, e.g., a DNA fragment which has been removed from thesequences which are normally adjacent to the fragment, e.g., thesequences adjacent to the fragment in a genome in which it naturallyoccurs. The term also applies to nucleic acids which have beensubstantially purified from other components which naturally accompanythe nucleic acid, e.g., RNA or DNA or proteins, which naturallyaccompany it in the cell. The term therefore includes, for example, arecombinant DNA which is incorporated into a vector, into anautonomously replicating plasmid or virus, or into the genomic DNA of aprokaryote or eukaryote, or which exists as a separate molecule (e.g.,as a cDNA or a genomic or cDNA fragment produced by PCR or restrictionenzyme digestion) independent of other sequences. It also includes arecombinant DNA which is part of a hybrid gene encoding additionalpolypeptide sequence.

As used herein, the term “NPP” or “ENPP” refers to ectonucleotidepyrophosphatase/phosphodiesterase.

A “nucleic acid” refers to a polynucleotide and includespoly-ribonucleotides and poly-deoxyribonucleotides. Nucleic acidsaccording to the present invention may include any polymer or oligomerof pyrimidine and purine bases, preferably cytosine, thymine, anduracil, and adenine and guanine, respectively. See Albert L. Lehninger,Principles of Biochemistry, at 793-800 (Worth Pub. 1982) which is hereinincorporated in its entirety for all purposes. Indeed, the presentinvention contemplates any deoxyribonucleotide, ribonucleotide orpeptide nucleic acid component, and any chemical variants thereof, suchas methylated, hydroxymethylated or glucosylated forms of these bases,and the like. The polymers or oligomers may be heterogeneous orhomogeneous in composition, and may be isolated from naturally occurringsources or may be artificially or synthetically produced. In addition,the nucleic acids may be DNA or RNA, or a mixture thereof, and may existpermanently or transitionally in single-stranded or double-strandedform, including homoduplex, heteroduplex, and hybrid states.

An “oligonucleotide” or “polynucleotide” is a nucleic acid ranging fromat least 2, in certain embodiments at least 8, 15 or 25 nucleotides inlength, but may be up to 50, 100, 1000, or 5000 nucleotides long or acompound that specifically hybridizes to a polynucleotide.Polynucleotides include sequences of deoxyribonucleic acid (DNA) orribonucleic acid (RNA) or mimetics thereof which may be isolated fromnatural sources, recombinantly produced or artificially synthesized. Afurther example of a polynucleotide of the present invention may be apeptide nucleic acid (PNA). (See U.S. Pat. No. 6,156,501 which is herebyincorporated by reference in its entirety) The invention alsoencompasses situations in which there is a nontraditional base pairingsuch as Hoogsteen base pairing which has been identified in certain tRNAmolecules and postulated to exist in a triple helix. “Polynucleotide”and “oligonucleotide” are used interchangeably herein. It is understoodthat when a nucleotide sequence is represented herein by a DNA sequence(e.g., A, T, G, and C), this also includes the corresponding RNAsequence (e.g., A, U, G, C) in which “U” replaces “T.”

As used herein, the term “patient,” “individual” or “subject” refers toa human or a non-human mammal. Non-human mammals include, for example,livestock and pets, such as ovine, bovine, porcine, canine, feline andmurine mammals. In certain embodiments, the patient, individual orsubject is human.

As used herein, the term “prevent” or “prevention” means no disorder ordisease development if none had occurred, or no further disorder ordisease development if there had already been development of thedisorder or disease. Also considered is the ability of one to preventsome or all of the symptoms associated with the disorder or disease.

As used herein, the term “pharmaceutical composition” or “composition”refers to a mixture of at least one compound useful within the inventionwith a pharmaceutically acceptable carrier. The pharmaceuticalcomposition facilitates administration of the compound to a patient.Multiple techniques of administering a compound exist in the artincluding, but not limited to, intravenous, oral, aerosol, inhalational,rectal, vaginal, transdermal, intranasal, buccal, sublingual,parenteral, intrathecal, intragastrical, ophthalmic, pulmonary andtopical administration.

As used herein, the term “pharmaceutically acceptable” refers to amaterial, such as a carrier or diluent, which does not abrogate thebiological activity or properties of the compound, and is relativelynon-toxic, i.e., the material may be administered to an individualwithout causing undesirable biological effects or interacting in adeleterious manner with any of the components of the composition inwhich it is contained.

As used herein, the term “pharmaceutically acceptable carrier” means apharmaceutically acceptable material, composition or carrier, such as aliquid or solid filler, stabilizer, dispersing agent, suspending agent,diluent, excipient, thickening agent, solvent or encapsulating material,involved in carrying or transporting a compound useful within theinvention within or to the patient such that it may perform its intendedfunction. Typically, such constructs are carried or transported from oneorgan, or portion of the body, to another organ, or portion of the body.Each carrier must be “acceptable” in the sense of being compatible withthe other ingredients of the formulation, including the compound usefulwithin the invention, and not injurious to the patient. Some examples ofmaterials that may serve as pharmaceutically acceptable carriersinclude: sugars, such as lactose, glucose and sucrose; starches, such ascorn starch and potato starch; cellulose, and its derivatives, such assodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate;powdered tragacanth; malt; gelatin; talc; excipients, such as cocoabutter and suppository waxes; oils, such as peanut oil, cottonseed oil,safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols,such as propylene glycol; polyols, such as glycerin, sorbitol, mannitoland polyethylene glycol; esters, such as ethyl oleate and ethyl laurate;agar; buffering agents, such as magnesium hydroxide and aluminumhydroxide; surface active agents; alginic acid; pyrogen-free water;isotonic saline; Ringer's solution; ethyl alcohol; phosphate buffersolutions; and other non-toxic compatible substances employed inpharmaceutical formulations. As used herein, “pharmaceuticallyacceptable carrier” also includes any and all coatings, antibacterialand antifungal agents, and absorption delaying agents, and the like thatare compatible with the activity of the compound useful within theinvention, and are physiologically acceptable to the patient.Supplementary active compounds may also be incorporated into thecompositions. The “pharmaceutically acceptable carrier” may furtherinclude a pharmaceutically acceptable salt of the compound useful withinthe invention. Other additional ingredients that may be included in thepharmaceutical compositions used in the practice of the invention areknown in the art and described, for example in Remington'sPharmaceutical Sciences (Genaro, Ed., Mack Publishing Co., 1985, Easton,Pa.), which is incorporated herein by reference.

As used herein, the language “pharmaceutically acceptable salt” refersto a salt of the administered compound prepared from pharmaceuticallyacceptable non-toxic acids and bases, including inorganic acids,inorganic bases, organic acids, inorganic bases, solvates, hydrates, andclathrates thereof. Suitable pharmaceutically acceptable acid additionsalts may be prepared from an inorganic acid or from an organic acid.Examples of inorganic acids include sulfate, hydrogen sulfate,hydrochloric, hydrobromic, hydriodic, nitric, carbonic, sulfuric, andphosphoric acids (including hydrogen phosphate and dihydrogenphosphate). Appropriate organic acids may be selected from aliphatic,cycloaliphatic, aromatic, araliphatic, heterocyclic, carboxylic andsulfonic classes of organic acids, examples of which include formic,acetic, propionic, succinic, glycolic, gluconic, lactic, malic,tartaric, citric, ascorbic, glucuronic, maleic, fumaric, pyruvic,aspartic, glutamic, benzoic, anthranilic, 4-hydroxybenzoic,phenylacetic, mandelic, embonic (pamoic), methanesulfonic,ethanesulfonic, benzenesulfonic, pantothenic, trifluoromethanesulfonic,2-hydroxyethanesulfonic, p-toluenesulfonic, sulfanilic,cyclohexylaminosulfonic, stearic, alginic, β-hydroxybutyric, salicylic,galactaric and galacturonic acid. Suitable pharmaceutically acceptablebase addition salts of compounds of the invention include, for example,metallic salts including alkali metal, alkaline earth metal andtransition metal salts such as, for example, calcium, magnesium,potassium, sodium and zinc salts. Pharmaceutically acceptable baseaddition salts also include organic salts made from basic amines suchas, for example, N,N′-dibenzylethylene-diamine, chloroprocaine, choline,diethanolamine, ethylenediamine, meglumine (N-methylglucamine) andprocaine. All of these salts may be prepared from the correspondingcompound by reacting, for example, the appropriate acid or base with thecompound.

As used herein, “polynucleotide” includes cDNA, RNA, DNA/RNA hybrid,antisense RNA, ribozyme, genomic DNA, synthetic forms, and mixedpolymers, both sense and antisense strands, and may be chemically orbiochemically modified to contain non-natural or derivatized, synthetic,or semi-synthetic nucleotide bases. Also, contemplated are alterationsof a wild type or synthetic gene, including but not limited to deletion,insertion, substitution of one or more nucleotides, or fusion to otherpolynucleotide sequences.

As used herein, the term “polypeptide” refers to a polymer composed ofamino acid residues, related naturally occurring structural variants,and synthetic non-naturally occurring analogs thereof linked via peptidebonds. Synthetic polypeptides may be synthesized, for example, using anautomated polypeptide synthesizer. As used herein, the term “protein”typically refers to large polypeptides. As used herein, the term“peptide” typically refers to short polypeptides. Conventional notationis used herein to represent polypeptide sequences: the left-hand end ofa polypeptide sequence is the amino-terminus, and the right-hand end ofa polypeptide sequence is the carboxyl-terminus.

As used herein, amino acids are represented by the full name thereof, bythe three letter code corresponding thereto, or by the one-letter codecorresponding thereto, as indicated below: Aspartic Acid (Asp/D);Glutamic Acid (Glu/E); Lysine (Lys/K); Arginine (Arg/R); Histidine(His/H); Tyrosine (Tyr/Y); Cysteine (Cys/C); Asparagine (Asn/N);Glutamine (Gln/Q); Serine (Ser/S); Threonine (Thr/T); Glycine (Gly/G);Alanine (Ala/A); Valine (Val/V); Leucine (Leu/L); Isoleucine (Ile/I);Methionine (Met/M); Proline (Pro/P); Phenylalanine (Phe/F); Tryptophan(Trp/W).

“Sample” or “biological sample” as used herein means a biologicalmaterial isolated from a subject. The biological sample may contain anybiological material suitable for detecting a mRNA, polypeptide or othermarker of a physiologic or pathologic process in a subject, and maycomprise fluid, tissue, cellular and/or non-cellular material obtainedfrom the individual.

By the term “specifically binds,” as used herein with respect to anantibody, is meant an antibody which recognizes a specific antigen, butdoes not substantially recognize or bind other molecules in a sample.For example, an antibody that specifically binds to an antigen from onespecies may also bind to that antigen from one or more species. But,such cross-species reactivity does not itself alter the classificationof an antibody as specific. In another example, an antibody thatspecifically binds to an antigen may also bind to different allelicforms of the antigen. However, such cross reactivity does not itselfalter the classification of an antibody as specific. In some instances,the terms “specific binding” or “specifically binding,” can be used inreference to the interaction of an antibody, a protein, or a peptidewith a second chemical species, to mean that the interaction isdependent upon the presence of a particular structure (e.g., anantigenic determinant or epitope) on the chemical species; for example,an antibody recognizes and binds to a specific protein structure ratherthan to proteins generally. If an antibody is specific for epitope “A”,the presence of a molecule containing epitope A (or free, unlabeled A),in a reaction containing labeled “A” and the antibody, will reduce theamount of labeled A bound to the antibody.

As used herein, “substantially purified” refers to being essentiallyfree of other components. For example, a substantially purifiedpolypeptide is a polypeptide which has been separated from othercomponents with which it is normally associated in its naturallyoccurring state.

As used herein, the term “treatment” or “treating” is defined as theapplication or administration of a therapeutic agent, i.e., a compounduseful within the invention (alone or in combination with anotherpharmaceutical agent), to a patient, or application or administration ofa therapeutic agent to an isolated tissue or cell line from a patient(e.g., for diagnosis or ex vivo applications), who has a disease ordisorder, a symptom of a disease or disorder or the potential to developa disease or disorder, with the purpose to cure, heal, alleviate,relieve, alter, remedy, ameliorate, improve or affect the disease ordisorder, the symptoms of the disease or disorder, or the potential todevelop the disease or disorder. Such treatments may be specificallytailored or modified, based on knowledge obtained from the field ofpharmacogenomics.

As used herein, the term “wild-type” refers to a gene or gene productisolated from a naturally occurring source. A wild-type gene is thatwhich is most frequently observed in a population and is thusarbitrarily designed the “normal” or “wild-type” form of the gene. Incontrast, the term “modified” or “mutant” refers to a gene or geneproduct that displays modifications in sequence and/or functionalproperties (i.e., altered characteristics) when compared to thewild-type gene or gene product. Naturally occurring mutants can beisolated; these are identified by the fact that they have alteredcharacteristics (including altered nucleic acid sequences) when comparedto the wild-type gene or gene product.

Ranges: throughout this disclosure, various aspects of the invention canbe presented in a range format. It should be understood that thedescription in range format is merely for convenience and brevity andshould not be construed as an inflexible limitation on the scope of theinvention. Accordingly, the description of a range should be consideredto have specifically disclosed all the possible subranges as well asindividual numerical values within that range. For example, descriptionof a range such as from 1 to 6 should be considered to have specificallydisclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numberswithin that range, for example, 1, 2, 2.7, 3, 4, 5, 5.3, and 6. Thisapplies regardless of the breadth of the range.

DESCRIPTION

ENPP1 is the primary source of extracellular PPi in the body. Despitethe multiple genetic etiologies and multifactorial nature of theexpression, progression, and severity of GACI, the present resultsdemonstrate that disruption of NPP1's extracellular purinergicmetabolism accounts for the pathologic sequela and mortality associatedwith GACI, and enzyme replacement therapy with ENPP1 is a tractabletherapeutic approach. This was demonstrated using the ENPP1-asj mousemodel of GACI on the ‘acceleration diet’.

Diseases of ectopic tissue calcification range from the ultra-rarediseases, such as GACI, to nearly ubiquitous maladies in the agingpopulation such as hardening of the arteries and osteoarthritis. Thegenetic etiology of human GACI suggests that the lethal arterialcalcifications result from impairment of extracellular purinergicmetabolism, either through loss of function mutations in ENPP1 orupstream reductions in nucleotide triphosphates metabolized by ENPP1into extracellular PPi. As demonstrated herein, subcutaneoussupplementation with untargeted ENPP1 or untargeted ENPP1-Fc increasesextracellular PPi concentrations sufficiently to eliminate themortality, as well as the cardiac and arterial calcifications in animalmodels of GACI. These results indicate that untargeted enzymereplacement therapy can be efficacious in GACI and other diseasesresulting in uncontrolled vascular calcification.

The present results are surprising in light of previous studies treatinghereditary hypophosphatasia (HPP), which claimed the necessity of abone-targeting motif for efficacy. HPP is a rickets-like disease ofreduced/absent of bone mineralization, and treatment with recombinantTNAP invoked the necessity of bone targeting to achieve a clinicaleffect (Millan, et al., 2008, J. Bone Mineral Res. 23:777-787; Whyte, etal., 2012, New Engl. J. Med. 366:904-913). Clinical trials attempting totreat HPP with serum enriched with untargeted TNAP failed (Whyte, etal., 1982, J. Pediatrics 101:379-386; Whyte, et al., 1984, J. Pediatrics105:926-933; Weninger, et al., 1989, Acta Paediatrica ScandinavicaSuppl. 360:154-160). Further, the literature at the time of theinvention indicated that untargeted NPP1 showed no efficacy with invitro calcification assays (WO 2012/125182 to Quinn, et al., such as forexample FIG. 23 therein), thus indicating that bone targeting wasessential for the biological activity of an NPP1 containing biologic invivo. However, in certain embodiments, the present results indicate thatbone-targeting is not necessary for therapeutic efficacy.

The arterial calcifications of GACI may be accompanied by extravascularcalcifications in the skin and retina that typify a second rare disease,PXE. PXE is a closely related to GACI, but instead results in ectopictissue mineralization of elastic fibers affecting the skin, eyes, andcardiovascular system. PXE has a later onset, slower progression, and isrelatively more common than GACI, with an incidence of 1/25,000 to1/75,000. The clinical manifestations begin in the skin with thedevelopment of small yellowish papules that coalesce into larger plaquesof leathery skin followed by angioid streaks in the eye leading tobleeding, scarring, neovascularization, progressive loss of visualacuity and blindness. The cardiovascular system may also be affected byprogressive mineralization of the medium sized arterial blood vessels,resulting in hypertension, claudication, occasional bleeding of theintestinal arteries, and (rarely) premature myocardial infarction. Thegenetic basis of PXE is loss of function mutations in the abcc6 gene,resulting in impaired function of the MRP6 protein, which reducesextracellular nucleotriphosphate (NTP) concentrations in vitro and invivo. This reduces ENPP1 substrate concentrations and thereby limitsextracellular production of PPi.

The NPP1-asj mouse model of GACI possesses both the genetic etiology andthe pathologic features of human GACI, but the mice also developperiarticular calcifications not characteristic of GACI but reminiscentof human diseases of unregulated periarticular calcification such asosteoarthritis and ossification of the posterior longitudinal ligament(OPLL). Mice possessing a missense mutation in ENPP1 (V246D) wereinitially described as ‘asj’ mice for ‘associated with stiffenedjoints’, reflecting the development of progressive periarticularcalcifications in the forepaws of the mice. ENPP1 mutations in mice areused to model paraspinal calcifications in ttw/ttw mice to provideinsight into OPLL, but identification of ENPP1 mutations in GACI led toa reappraisal of the presence of vascular calcifications in theseanimals and Uitto and coworkers noted that NPP1-asj mice, when fed aspecial diet high in Ca⁺² and low in Mg⁺², recapitulated many of theessential features of human GACI. ENPP1 protein levels correlateinversely with the severity of cartilage calcification andosteoarthritis in humans, and ENPP1 genetic variants account for asubstantial fraction of hand osteoarthritis in patient populationspredisposed to hereditary forms of the disease. In certain embodiments,ENPP1 enzyme replacement therapy is a viable treatment strategy forforms of osteoarthritis resulting from ENPP1 deficiency and/or areduction of extracellular PPi concentration. Such conditions include,but are not limited to, PXE, hereditary and non-hereditary forms ofosteoarthritis, ankylosing spondylitis, hardening of the arteriesoccurring with aging, and calciphylaxis resulting from end stage renaldisease.

COMPOSITIONS

In certain embodiments, the compositions of the invention comprises atleast one compound of formula (I), or a solvate or salt (such as apharmaceutically acceptable salt) thereof:

PROTEIN-Z-DOMAIN-X—Y  (I),

wherein in (I)

PROTEIN is at least one selected from the group consisting of NPP121(SEQ ID NO:15), NPP71 (SEQ ID NO:17), NPP71 lacking NPP1 N-terminus GLK(SEQ ID NO:19), and NPP51 (SEQ ID NO:24);

DOMAIN is at least one selected from the group consisting of a human IgGFc domain (Fc), human serum albumin protein (ALB) and a fragmentthereof;

X and Z are independently absent or a polypeptide comprising 1-20 aminoacids; and,

Y is absent or a sequence selected from the group consisting of:(DSS)_(n) (SEQ ID NO:4), (ESS)_(n) (SEQ ID NO:5), (RQQ)_(n) (SEQ IDNO:6), (KR)_(n) (SEQ ID NO:7), R_(m) (SEQ ID NO:8), DSSSEEKFLRRIGRFG(SEQ ID NO:9), EEEEEEEPRGDT (SEQ ID NO:10), APWHLSSQYSRT (SEQ ID NO:11),STLPIPHEFSRE (SEQ ID NO:12), VTKHLNQISQSY (SEQ ID NO:13), and E_(m) (SEQID NO:14) wherein m is an integer ranging from 1 to 15, and wherein n isan integer ranging from 1 to 10.

In certain embodiments, the compositions of the invention comprises atleast one compound of formula (II), or a pharmaceutical salt thereof:

PROTEIN-Z-DOMAIN-X—Y  (II),

wherein in (II)

PROTEIN is at least one selected from the group consisting of NPP121(SEQ ID NO:15), NPP71 (SEQ ID NO:17), NPP71 lacking NPP1 N-terminus GLK(SEQ ID NO:19), and NPP51 (SEQ ID NO:24);

DOMAIN is at least one selected from the group consisting of a human IgGFc domain (Fc), human serum albumin protein (ALB) and a fragmentthereof;

X and Z are independently absent or a polypeptide comprising 1-20 aminoacids; and,

Y is a sequence selected from the group consisting of: (DSS)_(n) (SEQ IDNO:4), (ESS)_(n) (SEQ ID NO:5), (RQQ)_(n) (SEQ ID NO:6), (KR)_(n) (SEQID NO:7), R_(m) (SEQ ID NO:8), DSSSEEKFLRRIGRFG (SEQ ID NO:9),EEEEEEEPRGDT (SEQ ID NO:10), APWHLSSQYSRT (SEQ ID NO:11), STLPIPHEFSRE(SEQ ID NO:12), VTKHLNQISQSY (SEQ ID NO:13), and E_(m) (SEQ ID NO:14),wherein m is an integer ranging from 1 to 15, and wherein n is aninteger ranging from 1 to 10.

In certain embodiments, DOMAIN comprises a human IgG Fc domain orfragment thereof. In other embodiments, DOMAIN consists essentially of ahuman IgG Fc domain or fragment thereof. In yet other embodiments,DOMAIN consists of a human IgG Fc domain or fragment thereof.

In certain embodiments, DOMAIN comprises a human serum albumin proteinor a fragment thereof. In other embodiments, DOMAIN consists essentiallyof a human serum albumin protein or a fragment thereof. In yet otherembodiments, DOMAIN consists of a human serum albumin protein or afragment thereof.

In certain embodiments, Y is a negatively-charged bone-targetingsequence. In certain embodiments, Y is absent. In certain embodiments, Yis absent and the compound of formula (I) or (II) lacks anegatively-charged bone-targeting sequence. In yet other embodiments, apolyaspartic acid domain and SEQ ID NOs:4-14 are non-limiting examplesof a negatively-charged bone-targeting sequence.

In certain embodiments, the PROTEIN has a mutation in at least oneposition selected from the group consisting of Ser 532, Tyr 529, Tyr451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relativeto SEQ ID NO:1. In other embodiments, the PROTEIN or mutant thereof istruncated to remove the nuclease domain. In yet other embodiments, thePROTEIN or mutant thereof is truncated to remove the nuclease domainfrom about residue 524 to about residue 885 relative to SEQ ID NO:1,leaving only the catalytic domain from about residue 186 to aboutresidue 586 relative to SEQ ID NO:1, which serves to preserve thecatalytic activity of the protein.

In certain embodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQID NO:15)-Z-(Fc or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1. In other embodiments,Z is a tripeptide. In yet other embodiments, Z is L I N. In yet otherembodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises SEQ ID NO:16, ora mutant thereof comprising at least one mutation in at least oneposition selected from the group consisting of Ser 532, Tyr 529, Tyr451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relativeto SEQ ID NO:1.

In certain embodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQID NO:17)-Z-(Fc or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1. In other embodiments,Z is a tripeptide. In yet other embodiments, Z is L I N. In yet otherembodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises SEQ ID NO:18, ora mutant thereof comprising at least one mutation in at least oneposition selected from the group consisting of Ser 532, Tyr 529, Tyr451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relativeto SEQ ID NO:1.

In certain embodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQID NO:19)-Z-(Fc or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1. In other embodiments,Z is a tripeptide. In yet other embodiments, Z is L I N. In yet otherembodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises SEQ ID NO:20, ora mutant thereof comprising at least one mutation in at least oneposition selected from the group consisting of Ser 532, Tyr 529, Tyr451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relativeto SEQ ID NO:1.

In certain embodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQID NO:24)-Z-(Fc or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1. In other embodiments,Z is a tripeptide. In yet other embodiments, Z is L I N. In yet otherembodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQ IDNO:24)-Z-(SEQ ID NO:26), or a mutant thereof comprising at least onemutation in at least one position selected from the group consisting ofSer 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346,Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448,Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343and Gly 536, relative to SEQ ID NO:1.

In certain embodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQID NO:15)-Z-(ALB or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1. In other embodiments,Z is a tripeptide. In yet other embodiments, Z is one selected from thegroup consisting of SEQ ID NOs:28-30. In yet other embodiments, in (I)or (II) PROTEIN-Z-DOMAIN comprises SEQ ID NO:21, or a mutant thereofcomprising at least one mutation in at least one position selected fromthe group consisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser525, Gly 342, Ser 343 and Gly 536, relative to SEQ ID NO:1.

In certain embodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQID NO:17)-Z-(ALB or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1. In other embodiments,Z is a tripeptide. In yet other embodiments, Z is one selected from thegroup consisting of SEQ ID NOs:28-30. In yet other embodiments, in (I)or (II) PROTEIN-Z-DOMAIN comprises (SEQ ID NO:17)-Z-(SEQ ID NO:27), or amutant thereof comprising at least one mutation in at least one positionselected from the group consisting of Ser 532, Tyr 529, Tyr 451, Ile450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relative to SEQ IDNO:1, wherein Z is one selected from the group consisting of SEQ IDNOs:28-30.

In certain embodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQID NO:19)-Z-(ALB or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1. In other embodiments,Z is a tripeptide. In yet other embodiments, Z is one selected from thegroup consisting of SEQ ID NOs:28-30. In yet other embodiments, in (I)or (II) PROTEIN-Z-DOMAIN comprises SEQ ID NO:22, or a mutant thereofcomprising at least one mutation in at least one position selected fromthe group consisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser525, Gly 342, Ser 343 and Gly 536, relative to SEQ ID NO:1.

In certain embodiments, in (I) or (II) PROTEIN-Z-DOMAIN comprises (SEQID NO:24)-Z-(ALB or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1. In other embodiments,Z is a tripeptide. In yet other embodiments, Z is one selected from thegroup consisting of SEQ ID NOs:28-30. In yet other embodiments, in (I)or (II) PROTEIN-Z-DOMAIN comprises SEQ ID NO:25, or a mutant thereofcomprising at least one mutation in at least one position selected fromthe group consisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser525, Gly 342, Ser 343 and Gly 536, relative to SEQ ID NO:1.

In certain embodiments, X and Z are independently absent or apolypeptide comprising 1-18 amino acids. In other embodiments, X and Zare independently absent or a polypeptide comprising 1-16 amino acids.In yet other embodiments, X and Z are independently absent or apolypeptide comprising 1-14 amino acids. In yet other embodiments, X andZ are independently absent or a polypeptide comprising 1-12 amino acids.In yet other embodiments, X and Z are independently absent or apolypeptide comprising 1-10 amino acids. In yet other embodiments, X andZ are independently absent or a polypeptide comprising 1-8 amino acids.In yet other embodiments, X and Z are independently absent or apolypeptide comprising 1-6 amino acids. In yet other embodiments, X andZ are independently absent or a polypeptide comprising 1-5 amino acids.In yet other embodiments, X and Z are independently absent or apolypeptide comprising 1-4 amino acids. In yet other embodiments, X andZ are independently absent or a polypeptide comprising 1-3 amino acids.In yet other embodiments, X and Z are independently absent or apolypeptide comprising 1-2 amino acids. In yet other embodiments, X andZ are independently absent or a single amino acid.

In certain embodiments, m is 1. In other embodiments, m is 2. In yetother embodiments, m is 3. In yet other embodiments, m is 4. In yetother embodiments, m is 5. In yet other embodiments, m is 6. In yetother embodiments, m is 7. In yet other embodiments, m is 8. In yetother embodiments, m is 9. In yet other embodiments, m is 10. In yetother embodiments, m is 11. In yet other embodiments, m is 12. In yetother embodiments, m is 13. In yet other embodiments, m is 14. In yetother embodiments, m is 15. In yet other embodiments, each occurrence ofm is independently selected from the group consisting of an integerranging from 1 to 15, from 2 to 15, from 3 to 15, from 4 to 15, from 5to 15, from 6 to 15, from 7 to 15, from 8 to 15, from 9 to 15, from 10to 15, from 11 to 15, from 12 to 15, from 13 to 15, from 14 to 15, from1 to 14, from 2 to 14, from 3 to 14, from 4 to 14, from 5 to 14, from 6to 14, from 7 to 14, from 8 to 14, from 9 to 14, from 10 to 14, from 11to 14, from 12 to 14, from 13 to 14, from 1 to 13, from 2 to 13, from 3to 13, from 4 to 13, from 5 to 13, from 6 to 13, from 7 to 13, from 8 to13, from 9 to 13, from 10 to 13, from 11 to 13, from 12 to 13, from 1 to12, from 2 to 12, from 3 to 12, from 4 to 12, from 5 to 12, from 6 to12, from 7 to 12, from 8 to 12, from 9 to 12, from 10 to 12, from 11 to12, from 1 to 11, from 2 to 11, from 3 to 11, from 4 to 11, from 5 to11, from 6 to 11, from 7 to 11, from 8 to 11, from 9 to 11, from 10 to11, from 1 to 10, from 2 to 10, from 3 to 10, from 4 to 10, from 5 to10, from 6 to 10, from 7 to 10, from 8 to 10, from 9 to 10, from 1 to 9,from 2 to 9, from 3 to 9, from 4 to 9, from 5 to 9, from 6 to 9, from 7to 9, from 8 to 9, from 1 to 8, from 2 to 8, from 3 to 8, from 4 to 8,from 5 to 8, from 6 to 8, from 7 to 8, from 1 to 7, from 2 to 7, from 3to 7, from 4 to 7, from 5 to 7, from 6 to 7, from 1 to 6, from 2 to 6,from 3 to 6, from 4 to 6, from 5 to 6, from 1 to 5, from 2 to 5, from 3to 5, from 4 to 5, from 1 to 4, from 2 to 4, from 3 to 4, from 1 to 3,from 2 to 3, and from 1 to 2.

In certain embodiments, n is 1. In other embodiments, n is 2. In yetother embodiments, n is 3. In yet other embodiments, n is 4. In yetother embodiments, n is 5. In yet other embodiments, n is 6. In yetother embodiments, n is 7. In yet other embodiments, n is 8. In yetother embodiments, n is 9. In yet other embodiments, n is 10. In yetother embodiments, each occurrence of n is independently selected fromthe group consisting of an integer ranging from 1 to 10, from 2 to 10,from 3 to 10, from 4 to 10, from 5 to 10, from 6 to 10, from 7 to 10,from 8 to 10, from 9 to 10, from 1 to 9, from 2 to 9, from 3 to 9, from4 to 9, from 5 to 9, from 6 to 9, from 7 to 9, from 8 to 9, from 1 to 8,from 2 to 8, from 3 to 8, from 4 to 8, from 5 to 8, from 6 to 8, from 7to 8, from 1 to 7, from 2 to 7, from 3 to 7, from 4 to 7, from 5 to 7,from 6 to 7, from 1 to 6, from 2 to 6, from 3 to 6, from 4 to 6, from 5to 6, from 1 to 5, from 2 to 5, from 3 to 5, from 4 to 5, from 1 to 4,from 2 to 4, from 3 to 4, from 1 to 3, from 2 to 3, and from 1 to 2.

In certain embodiments, the PROTEIN or mutant thereof is modified with asegment of the extracellular region of NPP2 containing a furin cleavagesite, as compared to SEQ ID NO:1. In other embodiments, the PROTEIN ormutant thereof is not modified with a segment of the extracellularregion of NPP2 containing a furin cleavage site, as compared to SEQ IDNO:1.

In certain embodiments, the PROTEIN or mutant thereof is modified with asegment of the extracellular region of NPP2 containing a signalpeptidase cleavage site, as compared to SEQ ID NO: 1. In otherembodiments, the PROTEIN or mutant thereof is not modified with asegment of the extracellular region of NPP2 containing a signalpeptidase cleavage site, as compared to SEQ ID NO: 1

In certain embodiments, the compound of formula (I) or (II) is soluble.In other embodiments, the compound of formula (I) or (II) is arecombinant polypeptide. In yet other embodiments, the compound offormula (I) or (II) includes an NPP1 polypeptide or mutant thereof thatlacks the NPP1 transmembrane domain. In yet other embodiments, thecompound of formula (I) or (II) includes an NPP1 polypeptide or mutantthereof, wherein the NPP1 transmembrane domain or mutant thereof hasbeen removed (and/or truncated) and replaced with the transmembranedomain of another polypeptide, such as, by way of non-limiting example,NPP2.

In certain embodiments, the compound of formula (I) or (II) comprises anNPP1 polypeptide or mutant thereof further comprising more than onetransmembrane domain.

In certain embodiments, NPP1 is C-terminally fused to the Fc domain ofhuman immunoglobulin 1 (IgG1).

In certain embodiments, NPP1 is C-terminally fused to human serumalbumin.

In certain embodiments, a fragment and/or variant of NPP1 is fused withhuman serum albumin or variants and/or fragments thereof. Human serumalbumin may be conjugated to NPP1 protein through a chemical linker,including but not limited to naturally occurring or engineered disulfidebonds, or by genetic fusion to NPP1, or a fragment and/or variantthereof.

In certain embodiment, the compound of formula (I) or (II) comprises anNPP1 polypeptide or mutant thereof comprising transmembrane domains ofNPP1 and another polypeptide, such as, by way of non-limiting example,NPP2.

In certain embodiments, the compound of the formula (I) has a sequenceselected from the group consisting of SEQ ID NOs:21, 22 and 25.

In certain embodiments, the compound of the formula (I) has a sequenceselected from the group consisting of SEQ ID NOs:21, 22, 25 and (SEQ IDNO:17)-Z-(SEQ ID NO:27).

In certain embodiments, the compound of the formula (I) has a sequenceselected from the group consisting of SEQ ID NOs:16, 18, 20 and (SEQ IDNO:24)-Z-(SEQ ID NO:26).

In certain embodiments, the compounds of the invention have more thanone transmembrane domain. In other embodiments, the compounds of theinvention are further pegylated. In yet other embodiments, the compoundsof the invention have more than one transmembrane domain and are furtherpegylated.

In certain embodiments, the compound of formula (I) or (II) has ak_(cat) value greater than or equal to about 3.4 (±0.4) s⁻¹ enzyme⁻¹,wherein the k_(cat) is determined by measuring the rate of hydrolysis ofATP for the compound.

In certain embodiments, the compound of formula (I) or (II) has a K_(M)value less than or equal to about 2 μM, wherein the K_(M) is determinedby measuring the rate of hydrolysis of ATP for the compound.

In certain embodiments, the compound of formula (I) or (II) isformulated as a liquid formulation.

The invention further provides a dry product form of a pharmaceuticalcomposition comprising a therapeutic amount of a compound of formula (I)or (II), whereby the dry product is reconstitutable to a solution of thecompound in liquid form.

Methods

The invention provides methods of treating or preventing disorders anddiseases in a subject where an increased activity or level of NPP1polypeptide, fragment, derivative, mutant, or mutant fragment thereof isdesirable. In certain embodiments, the subject is administered atherapeutically effective amount of at least one compound of theinvention.

The invention further provides a method of treating or preventing adisease or disorder associated with pathological calcification orpathological ossification in a subject in need thereof, the methodcomprising administering to the subject a therapeutically effectiveamount of at least one compound of formula (I) or (II), wherein thedisease comprises GACI, IIAC, OPLL, hypophosphatemic rickets,osteoarthritis, and calcification of atherosclerotic plaques.

The invention further provides a method of treating or preventing adisease or disorder associated with pathological calcification orpathological ossification in a subject in need thereof, the methodcomprising administering to the subject a therapeutically effectiveamount of at least one compound of formula (I) or (II), wherein thedisease comprises PXE, hereditary and non-hereditary forms ofosteoarthritis, ankylosing spondylitis, hardening of the arteriesoccurring with aging, or calciphylaxis resulting from end stage renaldisease.

The invention further provides a method of reducing or preventingcardiac and/or arterial calcifications in an infant afflicted withgeneralized arterial calcification of infancy (GACI). In certainembodiments, the method comprises administering to the infant atherapeutically effective amount of a compound comprising (or consistingof) an ecto-nucleotide pyrophosphate/phosphodiesterase-1 (NPP1)polypeptide comprising (or fused to) an IgG Fc domain, wherein thecompound lacks a polyaspartic acid domain, whereby the administering ofthe compound increases extracellular pyrophosphate (PPi) concentrations,thus reducing or preventing cardiac and/or arterial calcifications inthe infant.

The invention further provides a method of reducing or preventingcardiac and/or arterial calcifications in an infant afflicted withgeneralized arterial calcification of infancy (GACI). In certainembodiments, the method comprises administering to the infant atherapeutically effective amount of a compound comprising (or consistingof) an ecto-nucleotide pyrophosphate/phosphodiesterase-1 (NPP1)polypeptide comprising (or fused to) a human serum albumin domain orfragment thereof, wherein the compound lacks a polyaspartic acid domain,whereby the administering increases extracellular pyrophosphate (PPi)concentrations, thus reducing or preventing cardiac and/or arterialcalcifications in the infant.

In certain embodiments, the disorders and diseases comprise at least oneselected from the group consisting of GACI, IIAC, OPLL, hypophosphatemicrickets, osteoarthritis, progeria, and calcification of atheroscleroticplaques. In other embodiments, the disorders or diseases comprise atleast one selected from the group consisting of PXE, hereditary andnon-hereditary forms of osteoarthritis, ankylosing spondylitis,hardening of the arteries occurring with aging, progeria, andcalciphylaxis resulting from end stage renal disease.

In certain embodiments, the compound is administered acutely orchronically to the subject. In other embodiments, the compound isadministered locally, regionally or systemically to the subject. In yetother embodiments, the administration is subcutaneous. In yet otherembodiments, the subject is a mammal. In yet other embodiments, themammal is human.

In certain embodiments, the compound of formula (I) or (II), fragment ormutant thereof has lower Ap3A hydrolytic activity as compared to thecorresponding wild-type NPP1 polypeptide or fragment thereof. In otherembodiments, the compound of formula (I) or (II), fragment or mutantthereof has substantially the same ATP hydrolytic activity as comparedto the corresponding wild-type NPP1 polypeptide or fragment thereof. Inyet other embodiments, the compound of formula (I) or (II), fragment ormutant thereof has lower Ap3A hydrolytic activity and substantially thesame ATP hydrolytic activity as compared to the corresponding wild-typeNPP1 polypeptide or fragment thereof.

In certain embodiments, the NPP1 polypeptide comprises a cleavageproduct of a precursor NPP1 polypeptide comprising an NPP2 transmembranedomain.

In certain embodiments, the NPP2 transmembrane domain comprises residues12-30 of NCBI accession no. NP_001124335 (SEQ ID NO:2), whichcorresponds to IISLFTFAVGVNICLGFTA (SEQ ID NO:23).

In certain embodiments, administration of therapeutically effectiveamount comprises about 3-15 mg/kg qd of the NPP1-Fc polypeptide.

In certain embodiments, the administration results in reducing theinfant's extracellular pyrophosphate concentrations to a level that iswithin the range that is found in an infant not afflicted with GACI. Incertain embodiments, the infant presents and/or is diagnosed with“failure to thrive” prior to the administration.

One skilled in the art, based upon the disclosure provided herein, wouldunderstand that the invention is useful in subjects who, in whole (e.g.,systemically) or in part (e.g., locally, tissue, organ), are being, orwill be, treated for pathological calcification or ossification. Incertain embodiments, the invention is useful in treating or preventingpathological calcification or ossification. The skilled artisan willappreciate, based upon the teachings provided herein, that the diseasesand disorders treatable by the compositions and methods described hereinencompass any disease or disorder where a decrease in calcification orossification will promote a positive therapeutic outcome.

It will be appreciated by one of skill in the art, when armed with thepresent disclosure including the methods detailed herein, that theinvention is not limited to treatment of a disease or disorder once isestablished. Particularly, the symptoms of the disease or disorder neednot have manifested to the point of detriment to the subject; indeed,the disease or disorder need not be detected in a subject beforetreatment is administered. That is, significant pathology from diseaseor disorder does not have to occur before the present invention mayprovide benefit. Therefore, the present invention, as described morefully herein, includes a method for preventing diseases and disorders ina subject, in that a compound of formula (I) or (II), or a mutantthereof, as discussed elsewhere herein, can be administered to a subjectprior to the onset of the disease or disorder, thereby preventing thedisease or disorder from developing.

One of skill in the art, when armed with the disclosure herein, wouldappreciate that the prevention of a disease or disorder in a subjectencompasses administering to a subject a compound of formula (I) or(II), or a mutant thereof as a preventative measure against a disease ordisorder.

The invention encompasses administration of a compound of formula (I) or(II), or a mutant thereof to practice the methods of the invention; theskilled artisan would understand, based on the disclosure providedherein, how to formulate and administer the compound of formula (I) or(II), or a mutant thereof to a subject. However, the present inventionis not limited to any particular method of administration or treatmentregimen. This is especially true where it would be appreciated by oneskilled in the art, equipped with the disclosure provided herein,including the reduction to practice using an art-recognized model ofpathological calcification or ossification, that methods ofadministering a compound of the invention can be determined by one ofskill in the pharmacological arts.

Pharmaceutical Compositions and Formulations

The invention provides pharmaceutical compositions comprising a compoundof formula (I) or (II) within the methods of the invention.

Such a pharmaceutical composition is in a form suitable foradministration to a subject, or the pharmaceutical composition mayfurther comprise one or more pharmaceutically acceptable carriers, oneor more additional ingredients, or some combination of these. Thevarious components of the pharmaceutical composition may be present inthe form of a physiologically acceptable salt, such as in combinationwith a physiologically acceptable cation or anion, as is well known inthe art.

In an embodiment, the pharmaceutical compositions useful for practicingthe method of the invention may be administered to deliver a dose ofbetween 1 ng/kg/day and 100 mg/kg/day. In other embodiments, thepharmaceutical compositions useful for practicing the invention may beadministered to deliver a dose of between 1 ng/kg/day and 500 mg/kg/day.

The relative amounts of the active ingredient, the pharmaceuticallyacceptable carrier, and any additional ingredients in a pharmaceuticalcomposition of the invention will vary, depending upon the identity,size, and condition of the subject treated and further depending uponthe route by which the composition is to be administered. By way ofexample, the composition may comprise between about 0.1% and about 100%(w/w) active ingredient.

Pharmaceutical compositions that are useful in the methods of theinvention may be suitably developed for inhalational, oral, rectal,vaginal, parenteral, topical, transdermal, pulmonary, intranasal,buccal, ophthalmic, intrathecal, intravenous or another route ofadministration. Other contemplated formulations include projectednanoparticles, liposomal preparations, resealed erythrocytes containingthe active ingredient, and immunologically-based formulations. Theroute(s) of administration is readily apparent to the skilled artisanand depends upon any number of factors including the type and severityof the disease being treated, the type and age of the veterinary orhuman patient being treated, and the like.

The formulations of the pharmaceutical compositions described herein maybe prepared by any method known or hereafter developed in the art ofpharmacology. In general, such preparatory methods include the step ofbringing the active ingredient into association with a carrier or one ormore other accessory ingredients, and then, if necessary or desirable,shaping or packaging the product into a desired single- or multi-doseunit.

As used herein, a “unit dose” is a discrete amount of the pharmaceuticalcomposition comprising a predetermined amount of the active ingredient.The amount of the active ingredient is generally equal to the dosage ofthe active ingredient that would be administered to a subject or aconvenient fraction of such a dosage such as, for example, one-half orone-third of such a dosage. The unit dosage form may be for a singledaily dose or one of multiple daily doses (e.g., about 1 to 4 or moretimes per day). When multiple daily doses are used, the unit dosage formmay be the same or different for each dose.

Although the descriptions of pharmaceutical compositions provided hereinare principally directed to pharmaceutical compositions suitable forethical administration to humans, it is understood by the skilledartisan that such compositions are generally suitable for administrationto animals of all sorts. Modification of pharmaceutical compositionssuitable for administration to humans in order to render thecompositions suitable for administration to various animals is wellunderstood, and the ordinarily skilled veterinary pharmacologist candesign and perform such modification with merely ordinary, if any,experimentation. Subjects to which administration of the pharmaceuticalcompositions of the invention is contemplated include, but are notlimited to, humans and other primates, mammals including commerciallyrelevant mammals such as cattle, pigs, horses, sheep, cats, and dogs.

In certain embodiments, the compositions are formulated using one ormore pharmaceutically acceptable excipients or carriers. In certainembodiments, the pharmaceutical compositions comprise a therapeuticallyeffective amount of the active agent and a pharmaceutically acceptablecarrier. Pharmaceutically acceptable carriers, which are useful,include, but are not limited to, glycerol, water, saline, ethanol andother pharmaceutically acceptable salt solutions such as phosphates andsalts of organic acids. Examples of these and other pharmaceuticallyacceptable carriers are described in Remington's PharmaceuticalSciences, 1991, Mack Publication Co., New Jersey.

The carrier may be a solvent or dispersion medium containing, forexample, water, ethanol, polyol (for example, glycerol, propyleneglycol, and liquid polyethylene glycol, and the like), suitable mixturesthereof, and vegetable oils. The proper fluidity may be maintained, forexample, by the use of a coating such as lecithin, by the maintenance ofthe required particle size in the case of dispersion and by the use ofsurfactants. Prevention of the action of microorganisms may be achievedby various antibacterial and antifungal agents, for example, parabens,chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In manycases, isotonic agents, for example, sugars, sodium chloride, orpolyalcohols such as mannitol and sorbitol, are used in the composition.Prolonged absorption of the injectable compositions may be brought aboutby including in the composition an agent which delays absorption, forexample, aluminum monostearate or gelatin.

Formulations may be employed in admixtures with conventional excipients,i.e., pharmaceutically acceptable organic or inorganic carriersubstances suitable for oral, parenteral, nasal, intravenous,subcutaneous, enteral, or any other suitable mode of administration,known to the art. The pharmaceutical preparations may be sterilized andif desired mixed with auxiliary agents, e.g., lubricants, preservatives,stabilizers, wetting agents, emulsifiers, salts for influencing osmoticpressure buffers, coloring, flavoring and/or aromatic substances and thelike. They may also be combined where desired with other active agents,e.g., other analgesic agents.

As used herein, “additional ingredients” include, but are not limitedto, one or more of the following: excipients; surface active agents;dispersing agents; inert diluents; granulating and disintegratingagents; binding agents; lubricating agents; sweetening agents; flavoringagents; coloring agents; preservatives; physiologically degradablecompositions such as gelatin; aqueous vehicles and solvents; oilyvehicles and solvents; suspending agents; dispersing or wetting agents;emulsifying agents, demulcents; buffers; salts; thickening agents;fillers; emulsifying agents; antioxidants; antibiotics; antifungalagents; stabilizing agents; and pharmaceutically acceptable polymeric orhydrophobic materials. Other “additional ingredients” that may beincluded in the pharmaceutical compositions of the invention are knownin the art and described, for example in Genaro, ed., 1985, Remington'sPharmaceutical Sciences, Mack Publishing Co., Easton, Pa., which isincorporated herein by reference.

The composition of the invention may comprise a preservative from about0.005% to 2.0% by total weight of the composition. The preservative isused to prevent spoilage in the case of exposure to contaminants in theenvironment. Examples of preservatives useful in accordance with theinvention included but are not limited to those selected from the groupconsisting of benzyl alcohol, sorbic acid, parabens, imidurea andcombinations thereof. A particular preservative is a combination ofabout 0.5% to 2.0% benzyl alcohol and 0.05% to 0.5% sorbic acid.

The composition may include an antioxidant and a chelating agent, whichinhibit the degradation of the compound. Illustrative antioxidants forsome compounds are BHT, BHA, alpha-tocopherol and ascorbic acid in theillustrative range of about 0.01% to 0.3%, for example BHT in the rangeof 0.03% to 0.1% by weight by total weight of the composition. Thechelating agent may be present in an amount ranging from 0.01% to 0.5%by weight by total weight of the composition. Illustrative chelatingagents include edetate salts (e.g. disodium edetate) and citric acid inthe weight range of about 0.01% to 0.20%, for example in the range of0.02% to 0.10% by weight by total weight of the composition. Thechelating agent is useful for chelating metal ions in the composition,which may be detrimental to the shelf life of the formulation. While BHTand disodium edetate are illustrative antioxidant and chelating agentrespectively for some compounds, other suitable and equivalentantioxidants and chelating agents may be substituted therefore as wouldbe known to those skilled in the art.

Liquid suspensions may be prepared using conventional methods to achievesuspension of the active ingredient in an aqueous or oily vehicle.Aqueous vehicles include, for example, water, and isotonic saline. Oilyvehicles include, for example, almond oil, oily esters, ethyl alcohol,vegetable oils such as arachis, olive, sesame, or coconut oil,fractionated vegetable oils, and mineral oils such as liquid paraffin.Liquid suspensions may further comprise one or more additionalingredients including, but not limited to, suspending agents, dispersingor wetting agents, emulsifying agents, demulcents, preservatives,buffers, salts, flavorings, coloring agents, and sweetening agents. Oilysuspensions may further comprise a thickening agent. Known suspendingagents include, but are not limited to, sorbitol syrup, hydrogenatededible fats, sodium alginate, polyvinylpyrrolidone, gum tragacanth, gumacacia, and cellulose derivatives (e.g., sodium carboxymethylcellulose,hydroxypropylmethylcellulose, methylcellulose). Known dispersing orwetting agents include, but are not limited to, naturally-occurringphosphatides such as lecithin, condensation products of an alkyleneoxide with a fatty acid, with a long chain aliphatic alcohol, with apartial ester derived from a fatty acid and a hexitol, or with a partialester derived from a fatty acid and a hexitol anhydride (e.g.,polyoxyethylene stearate, heptadecaethyleneoxycetanol, polyoxyethylenesorbitol monooleate, and polyoxyethylene sorbitan monooleate,respectively). Known emulsifying agents include, but are not limited to,lecithin, and acacia. Known preservatives include, but are not limitedto, methyl, ethyl, or n-propyl para-hydroxybenzoates, ascorbic acid, andsorbic acid. Known sweetening agents include, for example, glycerol,propylene glycol, sorbitol, sucrose, and saccharin. Known thickeningagents for oily suspensions include, for example, beeswax, hardparaffin, and cetyl alcohol.

Liquid solutions of the active ingredient in aqueous or oily solventsmay be prepared in substantially the same manner as liquid suspensions,the primary difference being that the active ingredient is dissolved,rather than suspended in the solvent. As used herein, an “oily” liquidis one that comprises a carbon-containing liquid molecule and whichexhibits a less polar character than water. Liquid solutions of thepharmaceutical composition of the invention may comprise each of thecomponents described with regard to liquid suspensions, it beingunderstood that suspending agents will not necessarily aid dissolutionof the active ingredient in the solvent. Aqueous solvents include, forexample, water, and isotonic saline. Oily solvents include, for example,almond oil, oily esters, ethyl alcohol, vegetable oils such as arachis,olive, sesame, or coconut oil, fractionated vegetable oils, and mineraloils such as liquid paraffin.

Powdered and granular formulations of a pharmaceutical preparation ofthe invention may be prepared using known methods. Such formulations maybe administered directly to a subject, used, for example, to formtablets, to fill capsules, or to prepare an aqueous or oily suspensionor solution by addition of an aqueous or oily vehicle thereto. Each ofthese formulations may further comprise one or more of dispersing orwetting agent, a suspending agent, and a preservative. Additionalexcipients, such as fillers and sweetening, flavoring, or coloringagents, may also be included in these formulations.

A pharmaceutical composition of the invention may also be prepared,packaged, or sold in the form of oil-in-water emulsion or a water-in-oilemulsion. The oily phase may be a vegetable oil such as olive or arachisoil, a mineral oil such as liquid paraffin, or a combination of these.Such compositions may further comprise one or more emulsifying agentssuch as naturally occurring gums such as gum acacia or gum tragacanth,naturally-occurring phosphatides such as soybean or lecithinphosphatide, esters or partial esters derived from combinations of fattyacids and hexitol anhydrides such as sorbitan monooleate, andcondensation products of such partial esters with ethylene oxide such aspolyoxyethylene sorbitan monooleate. These emulsions may also containadditional ingredients including, for example, sweetening or flavoringagents.

Methods for impregnating or coating a material with a chemicalcomposition are known in the art, and include, but are not limited tomethods of depositing or binding a chemical composition onto a surface,methods of incorporating a chemical composition into the structure of amaterial during the synthesis of the material (i.e., such as with aphysiologically degradable material), and methods of absorbing anaqueous or oily solution or suspension into an absorbent material, withor without subsequent drying.

Administration/Dosing

The regimen of administration may affect what constitutes an effectiveamount. For example, several divided dosages, as well as staggereddosages may be administered daily or sequentially, or the dose may becontinuously infused, or may be a bolus injection. Further, the dosagesof the therapeutic formulations may be proportionally increased ordecreased as indicated by the exigencies of the therapeutic orprophylactic situation.

Administration of the compositions of the present invention to apatient, psucha s a mammal, such as a human, may be carried out usingknown procedures, at dosages and for periods of time effective to treata disease or disorder in the patient. An effective amount of thetherapeutic compound necessary to achieve a therapeutic effect may varyaccording to factors such as the activity of the particular compoundemployed; the time of administration; the rate of excretion of thecompound; the duration of the treatment; other drugs, compounds ormaterials used in combination with the compound; the state of thedisease or disorder, age, sex, weight, condition, general health andprior medical history of the patient being treated, and like factorswell-known in the medical arts. Dosage regimens may be adjusted toprovide the optimum therapeutic response. For example, several divideddoses may be administered daily or the dose may be proportionallyreduced as indicated by the exigencies of the therapeutic situation. Anon-limiting example of an effective dose range for a therapeuticcompound of the invention is from about 0.01 and 50 mg/kg of bodyweight/per day. One of ordinary skill in the art would be able to studythe relevant factors and make the determination regarding the effectiveamount of the therapeutic compound without undue experimentation.

The compound can be administered to an animal as frequently as severaltimes daily, or it may be administered less frequently, such as once aday, once a week, once every two weeks, once a month, or even lessfrequently, such as once every several months or even once a year orless. It is understood that the amount of compound dosed per day may beadministered, in non-limiting examples, every day, every other day,every 2 days, every 3 days, every 4 days, or every 5 days. For example,with every other day administration, a 5 mg per day dose may beinitiated on Monday with a first subsequent 5 mg per day doseadministered on Wednesday, a second subsequent 5 mg per day doseadministered on Friday, and so on. The frequency of the dose is readilyapparent to the skilled artisan and depends upon any number of factors,such as, but not limited to, the type and severity of the disease beingtreated, and the type and age of the animal.

Actual dosage levels of the active ingredients in the pharmaceuticalcompositions of this invention may be varied so as to obtain an amountof the active ingredient that is effective to achieve the desiredtherapeutic response for a particular patient, composition, and mode ofadministration, without being toxic to the patient.

A medical doctor, e.g., physician or veterinarian, having ordinary skillin the art may readily determine and prescribe the effective amount ofthe pharmaceutical composition required. For example, the physician orveterinarian could start doses of the compounds of the inventionemployed in the pharmaceutical composition at levels lower than thatrequired in order to achieve the desired therapeutic effect andgradually increase the dosage until the desired effect is achieved.

In particular embodiments, it is especially advantageous to formulatethe compound in dosage unit form for ease of administration anduniformity of dosage. Dosage unit form as used herein refers tophysically discrete units suited as unitary dosages for the patients tobe treated; each unit containing a predetermined quantity of therapeuticcompound calculated to produce the desired therapeutic effect inassociation with the required pharmaceutical vehicle. The dosage unitforms of the invention are dictated by and directly dependent on (a) theunique characteristics of the therapeutic compound and the particulartherapeutic effect to be achieved, and (b) the limitations inherent inthe art of compounding/formulating such a therapeutic compound for thetreatment of a disease or disorder in a patient.

In certain embodiments, the compositions of the invention areadministered to the patient in dosages that range from one to five timesper day or more. In other embodiments, the compositions of the inventionare administered to the patient in range of dosages that include, butare not limited to, once every day, every two, days, every three days toonce a week, and once every two weeks. It is readily apparent to oneskilled in the art that the frequency of administration of the variouscombination compositions of the invention varies from subject to subjectdepending on many factors including, but not limited to, age, disease ordisorder to be treated, gender, overall health, and other factors. Thus,the invention should not be construed to be limited to any particulardosage regime and the precise dosage and composition to be administeredto any patient will be determined by the attending physical taking allother factors about the patient into account.

Compounds of the invention for administration may be in the range offrom about 1 μg to about 7,500 mg, about 20 μg to about 7,000 mg, about40 μg to about 6,500 mg, about 80 to about 6,000 mg, about 100 μg toabout 5,500 mg, about 200 μg to about 5,000 mg, about 400 μg to about4,000 mg, about 800 μg to about 3,000 mg, about 1 mg to about 2,500 mg,about 2 mg to about 2,000 mg, about 5 mg to about 1,000 mg, about 10 mgto about 750 mg, about 20 mg to about 600 mg, about 30 mg to about 500mg, about 40 mg to about 400 mg, about 50 mg to about 300 mg, about 60mg to about 250 mg, about 70 mg to about 200 mg, about 80 mg to about150 mg, and any and all whole or partial increments therebetween.

In some embodiments, the dose of a compound of the invention is fromabout 0.5 and about 5,000 mg. In some embodiments, a dose of a compoundof the invention used in compositions described herein is less thanabout 5,000 mg, or less than about 4,000 mg, or less than about 3,000mg, or less than about 2,000 mg, or less than about 1,000 mg, or lessthan about 800 mg, or less than about 600 mg, or less than about 500 mg,or less than about 200 mg, or less than about 50 mg. Similarly, in someembodiments, a dose of a second compound as described herein is lessthan about 1,000 mg, or less than about 800 mg, or less than about 600mg, or less than about 500 mg, or less than about 400 mg, or less thanabout 300 mg, or less than about 200 mg, or less than about 100 mg, orless than about 50 mg, or less than about 40 mg, or less than about 30mg, or less than about 25 mg, or less than about 20 mg, or less thanabout 15 mg, or less than about 10 mg, or less than about 5 mg, or lessthan about 2 mg, or less than about 1 mg, or less than about 0.5 mg, andany and all whole or partial increments thereof.

In certain embodiments, the present invention is directed to a packagedpharmaceutical composition comprising a container holding atherapeutically effective amount of a compound of the invention, aloneor in combination with a second pharmaceutical agent; and instructionsfor using the compound to treat, prevent, or reduce one or more symptomsof a disease or disorder in a patient.

The term “container” includes any receptacle for holding thepharmaceutical composition. For example, In certain embodiments, thecontainer is the packaging that contains the pharmaceutical composition.In other embodiments, the container is not the packaging that containsthe pharmaceutical composition, i.e., the container is a receptacle,such as a box or vial that contains the packaged pharmaceuticalcomposition or unpackaged pharmaceutical composition and theinstructions for use of the pharmaceutical composition. Moreover,packaging techniques are well known in the art. It should be understoodthat the instructions for use of the pharmaceutical composition may becontained on the packaging containing the pharmaceutical composition,and as such the instructions form an increased functional relationshipto the packaged product. However, it should be understood that theinstructions may contain information pertaining to the compound'sability to perform its intended function, e.g., treating, preventing, orreducing a disease or disorder in a patient.

Routes of Administration

Routes of administration of any of the compositions of the inventioninclude inhalational, oral, nasal, rectal, parenteral, sublingual,transdermal, transmucosal (e.g., sublingual, lingual, (trans)buccal,(trans)urethral, vaginal (e.g., trans- and perivaginally), (intra)nasal,and (trans)rectal), intravesical, intrapulmonary, intraduodenal,intragastrical, intrathecal, subcutaneous, intramuscular, intradermal,intra-arterial, intravenous, intrabronchial, inhalation, and topicaladministration.

Suitable compositions and dosage forms include, for example, tablets,capsules, caplets, pills, gel caps, troches, dispersions, suspensions,solutions, syrups, granules, beads, transdermal patches, gels, powders,pellets, magmas, lozenges, creams, pastes, plasters, lotions, discs,suppositories, liquid sprays for nasal or oral administration, drypowder or aerosolized formulations for inhalation, compositions andformulations for intravesical administration and the like. It should beunderstood that the formulations and compositions that would be usefulin the present invention are not limited to the particular formulationsand compositions that are described herein.

Oral Administration

For oral application, particularly suitable are tablets, dragees,liquids, drops, suppositories, or capsules, caplets and gelcaps. Otherformulations suitable for oral administration include, but are notlimited to, a powdered or granular formulation, an aqueous or oilysuspension, an aqueous or oily solution, a paste, a gel, toothpaste, amouthwash, a coating, an oral rinse, or an emulsion. The compositionsintended for oral use may be prepared according to any method known inthe art and such compositions may contain one or more agents selectedfrom the group consisting of inert, non-toxic pharmaceuticallyexcipients that are suitable for the manufacture of tablets. Suchexcipients include, for example an inert diluent such as lactose;granulating and disintegrating agents such as cornstarch; binding agentssuch as starch; and lubricating agents such as magnesium stearate.

Tablets may be non-coated or they may be coated using known methods toachieve delayed disintegration in the gastrointestinal tract of asubject, thereby providing sustained release and absorption of theactive ingredient. By way of example, a material such as glycerylmonostearate or glyceryl distearate may be used to coat tablets. Furtherby way of example, tablets may be coated using methods described in U.S.Pat. Nos. 4,256,108; 4,160,452; and 4,265,874 to form osmoticallycontrolled release tablets. Tablets may further comprise a sweeteningagent, a flavoring agent, a coloring agent, a preservative, or somecombination of these in order to provide for pharmaceutically elegantand palatable preparation.

Hard capsules comprising the active ingredient may be made using aphysiologically degradable composition, such as gelatin. Such hardcapsules comprise the active ingredient, and may further compriseadditional ingredients including, for example, an inert solid diluentsuch as calcium carbonate, calcium phosphate, or kaolin.

Soft gelatin capsules comprising the active ingredient may be made usinga physiologically degradable composition, such as gelatin. Such softcapsules comprise the active ingredient, which may be mixed with wateror an oil medium such as peanut oil, liquid paraffin, or olive oil.

For oral administration, the compounds of the invention may be in theform of tablets or capsules prepared by conventional means withpharmaceutically acceptable excipients such as binding agents; fillers;lubricants; disintegrates; or wetting agents. If desired, the tabletsmay be coated using suitable methods and coating materials such asOPADRY™ film coating systems available from Colorcon, West Point, Pa.(e.g., OPADRY™ OY Type, OYC Type, Organic Enteric OY-P Type, AqueousEnteric OY-A Type, OY-PM Type and OPADRY™ White, 32K18400).

Liquid preparation for oral administration may be in the form ofsolutions, syrups or suspensions. The liquid preparations may beprepared by conventional means with pharmaceutically acceptableadditives such as suspending agents (e.g., sorbitol syrup, methylcellulose or hydrogenated edible fats); emulsifying agent (e.g.,lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily estersor ethyl alcohol); and preservatives (e.g., methyl or propylpara-hydroxy benzoates or sorbic acid). Liquid formulations of apharmaceutical composition of the invention which are suitable for oraladministration may be prepared, packaged, and sold either in liquid formor in the form of a dry product intended for reconstitution with wateror another suitable vehicle prior to use.

A tablet comprising the active ingredient may, for example, be made bycompressing or molding the active ingredient, optionally with one ormore additional ingredients. Compressed tablets may be prepared bycompressing, in a suitable device, the active ingredient in afree-flowing form such as a powder or granular preparation, optionallymixed with one or more of a binder, a lubricant, an excipient, a surfaceactive agent, and a dispersing agent. Molded tablets may be made bymolding, in a suitable device, a mixture of the active ingredient, apharmaceutically acceptable carrier, and at least sufficient liquid tomoisten the mixture. Pharmaceutically acceptable excipients used in themanufacture of tablets include, but are not limited to, inert diluents,granulating and disintegrating agents, binding agents, and lubricatingagents. Known dispersing agents include, but are not limited to, potatostarch and sodium starch glycollate. Known surface-active agentsinclude, but are not limited to, sodium lauryl sulphate. Known diluentsinclude, but are not limited to, calcium carbonate, sodium carbonate,lactose, microcrystalline cellulose, calcium phosphate, calcium hydrogenphosphate, and sodium phosphate. Known granulating and disintegratingagents include, but are not limited to, corn starch and alginic acid.Known binding agents include, but are not limited to, gelatin, acacia,pre-gelatinized maize starch, polyvinylpyrrolidone, and hydroxypropylmethylcellulose. Known lubricating agents include, but are not limitedto, magnesium stearate, stearic acid, silica, and talc.

Granulating techniques are well known in the pharmaceutical art formodifying starting powders or other particulate materials of an activeingredient. The powders are typically mixed with a binder material intolarger permanent free-flowing agglomerates or granules referred to as a“granulation.” For example, solvent-using “wet” granulation processesare generally characterized in that the powders are combined with abinder material and moistened with water or an organic solvent underconditions resulting in the formation of a wet granulated mass fromwhich the solvent must then be evaporated.

Melt granulation generally consists in the use of materials that aresolid or semi-solid at room temperature (i.e. having a relatively lowsoftening or melting point range) to promote granulation of powdered orother materials, essentially in the absence of added water or otherliquid solvents. The low melting solids, when heated to a temperature inthe melting point range, liquefy to act as a binder or granulatingmedium. The liquefied solid spreads itself over the surface of powderedmaterials with which it is contacted, and on cooling, forms a solidgranulated mass in which the initial materials are bound together. Theresulting melt granulation may then be provided to a tablet press or beencapsulated for preparing the oral dosage form. Melt granulationimproves the dissolution rate and bioavailability of an active (i.e.drug) by forming a solid dispersion or solid solution.

U.S. Pat. No. 5,169,645 discloses directly compressible wax-containinggranules having improved flow properties. The granules are obtained whenwaxes are admixed in the melt with certain flow improving additives,followed by cooling and granulation of the admixture. In certainembodiments, only the wax itself melts in the melt combination of thewax(es) and additives(s), and in other cases both the wax(es) and theadditives(s) will melt.

The present invention also includes a multi-layer tablet comprising alayer providing for the delayed release of one or more compounds usefulwithin the methods of the invention, and a further layer providing forthe immediate release of one or more compounds useful within the methodsof the invention. Using a wax/pH-sensitive polymer mix, a gastricinsoluble composition may be obtained in which the active ingredient isentrapped, ensuring its delayed release.

Parenteral Administration

As used herein, “parenteral administration” of a pharmaceuticalcomposition includes any route of administration characterized byphysical breaching of a tissue of a subject and administration of thepharmaceutical composition through the breach in the tissue. Parenteraladministration thus includes, but is not limited to, administration of apharmaceutical composition by injection of the composition, byapplication of the composition through a surgical incision, byapplication of the composition through a tissue-penetrating non-surgicalwound, and the like. In particular, parenteral administration iscontemplated to include, but is not limited to, subcutaneous,intravenous, intraperitoneal, intramuscular, intrasternal injection, andkidney dialytic infusion techniques.

Formulations of a pharmaceutical composition suitable for parenteraladministration comprise the active ingredient combined with apharmaceutically acceptable carrier, such as sterile water or sterileisotonic saline. Such formulations may be prepared, packaged, or sold ina form suitable for bolus administration or for continuousadministration. Injectable formulations may be prepared, packaged, orsold in unit dosage form, such as in ampules or in multi-dose containerscontaining a preservative. Formulations for parenteral administrationinclude, but are not limited to, suspensions, solutions, emulsions inoily or aqueous vehicles, pastes, and implantable sustained-release orbiodegradable formulations. Such formulations may further comprise oneor more additional ingredients including, but not limited to,suspending, stabilizing, or dispersing agents. In one embodiment of aformulation for parenteral administration, the active ingredient isprovided in dry (i.e., powder or granular) form for reconstitution witha suitable vehicle (e.g., sterile pyrogen-free water) prior toparenteral administration of the reconstituted composition.

The pharmaceutical compositions may be prepared, packaged, or sold inthe form of a sterile injectable aqueous or oily suspension or solution.This suspension or solution may be formulated according to the knownart, and may comprise, in addition to the active ingredient, additionalingredients such as the dispersing agents, wetting agents, or suspendingagents described herein. Such sterile injectable formulations may beprepared using a non-toxic parenterally-acceptable diluent or solvent,such as water or 1,3-butanediol, for example. Other acceptable diluentsand solvents include, but are not limited to, Ringer's solution,isotonic sodium chloride solution, and fixed oils such as syntheticmono- or di-glycerides. Other parentally-administrable formulationswhich are useful include those which comprise the active ingredient inmicrocrystalline form, in a liposomal preparation, or as a component ofa biodegradable polymer system. Compositions for sustained release orimplantation may comprise pharmaceutically acceptable polymeric orhydrophobic materials such as an emulsion, an ion exchange resin, asparingly soluble polymer, or a sparingly soluble salt.

Additional Administration Forms

Additional dosage forms of this invention include dosage forms asdescribed in U.S. Pat. Nos. 6,340,475, 6,488,962, 6,451,808, 5,972,389,5,582,837, and 5,007,790. Additional dosage forms of this invention alsoinclude dosage forms as described in U.S. Patent Applications Nos.20030147952, 20030104062, 20030104053, 20030044466, 20030039688, and20020051820. Additional dosage forms of this invention also includedosage forms as described in PCT Applications Nos. WO 03/35041, WO03/35040, WO 03/35029, WO 03/35177, WO 03/35039, WO 02/96404, WO02/32416, WO 01/97783, WO 01/56544, WO 01/32217, WO 98/55107, WO98/11879, WO 97/47285, WO 93/18755, and WO 90/11757.

Controlled Release Formulations and Drug Delivery Systems

Controlled- or sustained-release formulations of a pharmaceuticalcomposition of the invention may be made using conventional technology.In some cases, the dosage forms to be used can be provided as slow orcontrolled-release of one or more active ingredients therein using, forexample, hydropropylmethyl cellulose, other polymer matrices, gels,permeable membranes, osmotic systems, multilayer coatings,microparticles, liposomes, or microspheres or a combination thereof toprovide the desired release profile in varying proportions. Suitablecontrolled-release formulations known to those of ordinary skill in theart, including those described herein, can be readily selected for usewith the pharmaceutical compositions of the invention. Thus, single unitdosage forms suitable for oral administration, such as tablets,capsules, gelcaps, and caplets, which are adapted for controlled-releaseare encompassed by the present invention.

Most controlled-release pharmaceutical products have a common goal ofimproving drug therapy over that achieved by their non-controlledcounterparts. Ideally, the use of an optimally designedcontrolled-release preparation in medical treatment is characterized bya minimum of drug substance being employed to cure or control thecondition in a minimum amount of time. Advantages of controlled-releaseformulations include extended activity of the drug, reduced dosagefrequency, and increased patient compliance. In addition,controlled-release formulations can be used to affect the time of onsetof action or other characteristics, such as blood level of the drug, andthus can affect the occurrence of side effects.

Most controlled-release formulations are designed to initially releasean amount of drug that promptly produces the desired therapeutic effect,and gradually and continually release of other amounts of drug tomaintain this level of therapeutic effect over an extended period oftime. In order to maintain this constant level of drug in the body, thedrug must be released from the dosage form at a rate that will replacethe amount of drug being metabolized and excreted from the body.

Controlled-release of an active ingredient can be stimulated by variousinducers, for example pH, temperature, enzymes, water, or otherphysiological conditions or compounds. The term “controlled-releasecomponent” in the context of the present invention is defined herein asa compound or compounds, including, but not limited to, polymers,polymer matrices, gels, permeable membranes, liposomes, or microspheresor a combination thereof that facilitates the controlled-release of theactive ingredient.

In certain embodiments, the formulations of the present invention maybe, but are not limited to, short-term, rapid-offset, as well ascontrolled, for example, sustained release, delayed release andpulsatile release formulations.

The term sustained release is used in its conventional sense to refer toa drug formulation that provides for gradual release of a drug over anextended period of time, and that may, although not necessarily, resultin substantially constant blood levels of a drug over an extended timeperiod. The period of time may be as long as a month or more and shouldbe a release which is longer that the same amount of agent administeredin bolus form. For sustained release, the compounds may be formulatedwith a suitable polymer or hydrophobic material which provides sustainedrelease properties to the compounds. As such, the compounds for use themethod of the invention may be administered in the form ofmicroparticles, for example, by injection or in the form of wafers ordiscs by implantation. In certain embodiments of the invention, thecompounds of the invention are administered to a patient, alone or incombination with another pharmaceutical agent, using a sustained releaseformulation.

The term delayed release is used herein in its conventional sense torefer to a drug formulation that provides for an initial release of thedrug after some delay following drug administration and that mat,although not necessarily, includes a delay of from about 10 minutes upto about 12 hours. The term pulsatile release is used herein in itsconventional sense to refer to a drug formulation that provides releaseof the drug in such a way as to produce pulsed plasma profiles of thedrug after drug administration. The term immediate release is used inits conventional sense to refer to a drug formulation that provides forrelease of the drug immediately after drug administration.

As used herein, short-term refers to any period of time up to andincluding about 8 hours, about 7 hours, about 6 hours, about 5 hours,about 4 hours, about 3 hours, about 2 hours, about 1 hour, about 40minutes, about 20 minutes, or about 10 minutes and any or all whole orpartial increments thereof after drug administration after drugadministration.

As used herein, rapid-offset refers to any period of time up to andincluding about 8 hours, about 7 hours, about 6 hours, about 5 hours,about 4 hours, about 3 hours, about 2 hours, about 1 hour, about 40minutes, about 20 minutes, or about 10 minutes, and any and all whole orpartial increments thereof after drug administration.

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, numerous equivalents to thespecific procedures, embodiments, claims, and examples described herein.Such equivalents were considered to be within the scope of thisinvention and covered by the claims appended hereto. For example, itshould be understood, that modifications in reaction conditions,including but not limited to reaction times, reaction size/volume, andexperimental reagents, such as solvents, catalysts, pressures,atmospheric conditions, e.g., nitrogen atmosphere, andreducing/oxidizing agents, with art-recognized alternatives and using nomore than routine experimentation, are within the scope of the presentapplication.

It is to be understood that wherever values and ranges are providedherein, all values and ranges encompassed by these values and ranges,are meant to be encompassed within the scope of the present invention.Moreover, all values that fall within these ranges, as well as the upperor lower limits of a range of values, are also contemplated by thepresent application.

The following examples further illustrate aspects of the presentinvention. However, they are in no way a limitation of the teachings ordisclosure of the present invention as set forth herein.

EXAMPLES

The invention is now described with reference to the following Examples.These Examples are provided for the purpose of illustration only, andthe invention is not limited to these Examples, but rather encompassesall variations that are evident as a result of the teachings providedherein.

Methods and Materials: ENPP1-asj GACI Mouse Model:

Heterozygous ENPP1-asj/+ breeding pairs were maintained on the‘acceleration diet’ (TD00.442, Harlan Laboratories, Madison Wis.)throughout the entire experiment to generate ENPP1-WT and ENPP1-asj/asjsibling pairs that had been exposed to the acceleration diet in utero.Liters were genotyped on day 8 and weaned at day 21. Following weaning,sibling pairs were divided into experimental cohorts and allexperimental animals were maintained on the acceleration diet throughcompletion of the study.

ENPP1-Fc Design:

Modified, human and mouse NPP1 (Human: NCBI accession NP_006199; Mouse:NCBI accession NP_03839) modified to express soluble, recombinantprotein was fused to IgG1 by subcloning into pFUSE-hIgG1-Fc1 orpFUSE-mIgG1-Fc1 plasmids (InvivoGen, San Diego Calif.), respectively.

Protein Production:

Shaking flasks: Stable transfections of the ENPP1-Fc were established inHEK293 cells under zeocin selection, and adherent HEK293 cells wereadapted for suspension growth. Adapted cells were used to seed liquidculture growths in FreeStyle medium (Gibco #12338-018) in shaker flasksat 37° C. and 5% CO₂, agitated at 120 rpm with high humidity. Theculture was gradually expanded to the desired target volume and thenmaintained for another 12 days to accumulate extracellular protein.During the maintenance phase, cultures were supplemented with CDEfficientFeed C AGT (Gibco #A13275-05) to enhance protein production.

Bioreactor: Cells were propagated in a 10 liter bioreactor equipped withdissolved oxygen and pH control. Dissolved oxygen was kept at 40% airsaturation by supplying the culture with mixture of air and oxygen notexceeding 3 liter per minute at an agitation rate of 80 RPM. pH wascontrolled at 7.4 by sparging CO₂ when the pH was higher than 7.4.Culture growth was followed by measuring cell number, cell viability,glucose and lactate concentrations. Final yields for both methods ofproduction were approximately 5 mg of purified ENPP1-Fc per liter ofculture.

Protein Purification:

The liquid cultures were centrifuged at 4300×g for 15 min and thesupernatants were filtered through a 0.2 μm membrane and concentratedvia tangential flow using a Pellicon®3 0.11 m² Ultracell® 30 kD cassette(Millipore, Billerica Mass.). The concentrated supernatant was thenpurified by a combination of chromatographic techniques in a mutli-stepprocess. These techniques are performed sequentially and may include anyof the following: affinity chromatography with protein A or protein G,cation-exchange chromatography, anion-exchange chromatography, sizeexclusion chromatography, hydrophobic exchange chromatography,high-pressure liquid chromatography (HPLC), precipitation steps,extractions steps, lyophylizations steps, and/or crystallization steps.Using any one of these steps in series, one schooled in the art ofprotein chemistry can purify the compositions of matter described tohomogeneity such that there are no contaminating protein bands on asilver stained gel (in a non-limiting exemplification, FIG. 10). Theresulting protein samples then tested with Pierce LAL ChromogenicEndotoxin Quantitation Kit (cat. 88282) to verify that all were free ofendotoxin.

Enzymology:

The steady state hydrolysis of ATP by human NPP1 was determined by HPLC.Briefly, enzyme reactions were started by addition of 10 nM NPP1 tovarying concentrations of ATP in the reaction buffer containing 20 mMTris, pH 7.4, 150 mM NaCl, 4.5 mM KCl, 14 μM ZnCl₂, 1 mM MgCl₂ and 1 mMCaCl₂. At various time points, 50 μL reaction solution were removed andquenched with an equal volume of 3M formic acid. The quenched reactionsolution was loaded on a C-18 (5 μm 250×4.6 mm) column (HigginsAnalytical) equilibrated in 15 mM ammonium acetate (pH 6.0) solution andeluted with a 0% to 20% methanol gradient. Substrate and products weremonitored by UV absorbance at 259 nm and quantified according to theintegration of their correspondent peaks and standard curves.

Vehicle:

-   -   mENPP1-Fc was formulated in vehicle such that the volume of        vehicle delivered was 16 μl vehicle/gram of body weight. Vehicle        consisted of americanBio 10×PBS (Stock #AB11072) diluted to 1×        with endotoxin free water and supplemented with 14 μM CaCl₂ and        14 μM ZnCl₂.

Dosing:

Animals were dosed either with vehicle or with mouse ENPP1-Fc(mENPP1-Fc) formulated in vehicle. Mice were dosed with dailysubcutaneous injections starting on day 14 at dose levels of 500 au/KgmENPP1-Fc.

Enzyme Activity:

In certain embodiments, enzymes useful within the invention haveenzymatic activity with the Michaelis Menton constants as described inAlbright, et al., 2015, Nature Comm. 6:10006 (K_(M)˜2 μM for ATPhydrolysis; k_(cat) of 3.46 (±0.44) s⁻¹).

Quantification of Plasma PPi:

ENPP1-WT and dosed ENPP1-asj/asj animals were terminally bledretro-orbitally using heparinized micropipttes, and the blood wasimmediately dispensed into heparin-treated eppendorf tubes and placed onwet ice. The samples were spun in a 4° C. pre-cooled microcentrifuge at4000 rpm for 5 minutes, and plasma was collected and diluted in onevolume of 50 mM Tris-Acetate pH=8.0 and frozen at −80° C. Quantitationof serum PPi was performed using as described previously (Cheung &Suhadolnik, 1977, Anal Biochem 83:61-63).

Micro-CT Scans:

In vivo ^(99m)PYP imaging: The bone imaging agent ^(99m)Tc-pyrophosphate(Pharmalucence, Inc) was evaluated in cohorts of animals using apreclinical microSPECT/CT hybrid imaging system with dual 1 mm pinholecollimators (X-SPECT, Gamma Medica-Ideas). Each animal was injected ipwith 2-5 mCi of the radiolabeled tracer and imaged 1-1.5 hr afterinjection. A CT scan (512 projections at 50 kVp, 800 uA and amagnification factor of 1.25) was acquired for anatomicalco-localization with the SPECT image. The SPECT imaging was acquiredwith 180° per collimator head in a counter-clockwise rotation, 32projections, 60 seconds per projection with an ROR of 7.0 cm, FOV of8.95 cm and an energy window of 140 keV±20. CT images were reconstructedwith the FLEX X-O CT software (Gamma Medica-Ideas) using a filteredback-projection algorithm. SPECT images were reconstructed using FLEXSPECT software (5 iterations, 4 subsets) and subsequently fused with theCT images and analyzed using AMIRA software and offline in-house script.Data was corrected for decay and injected dose to achieve % injecteddose (% ID).

Quantification of ^(99m)PYP uptake: For the ^(99m)PYP murine scans, theanimals were imaged two hours postinjection. The resulting SPECT scanswere imported into NIH's ImageJ image processing software and ROI's weredrawn around each animal's head (target organ) and whole body. Percentinjected activity (PIA), often referred to as “percent injected dose” (%ID) was calculated by comparing the ratio of counts in the head to thecounts in the whole body, and expressed as % ID to give a measure as ofthe affinity with which the radiotracer is taken up by the ROI (head).The total counts in each scan were taken as the whole body measure ofinjected dose.

Sequences: NPP1 Amino Acid Sequence (NCBI accession NP_006199)(SEQ ID NO: 1)MERDGCAGGGSRGGEGGRAPREGPAGNGRDRGRSHAAEAPGDPQAAASLLAPMDVGEEPLEKAARARTAKDPNTYKVLSLVLSVCVLTTILGCIFGLKPSCAKEVKSCKGRCFERTFGNCRCDAACVELGNCCLDYQETCIEPEHIWTCNKFRCGEKRLTRSLCACSDDCKDKGDCCINYSSVCQGEKSWVEEPCESINEPQCPAGFETPPTLLFSLDGFRAEYLHTWGGLLPVISKLKKCGTYTKNMRPVYPTKTFPNHYSIVTGLYPESHGIIDNKMYDPKMNASFSLKSKEKFNPEWYKGEPIWVTAKYQGLKSGTFFWPGSDVEINGIFPDIYKMYNGSVPFEERILAVLQWLQLPKDERPHFYTLYLEEPDSSGHSYGPVSSEVIKALQRVDGMVGMLMDGLKELNLHRCLNLILISDHGMEQGSCKKYIYLNKYLGDVKNIKVIYGPAARLRPSDVPDKYYSFNYEGIARNLSCREPNQHFKPYLKHFLPKRLHFAKSDRIEPLTFYLDPQWQLALNPSERKYCGSGFHGSDNVESNMQALFVGYGPGEKHGIEADTFENIEVYNLMCDLLNLTPAPNNGTHGSLNHLLKNPVYTPKHPKEVHPLVQCPFTRNPRDNLGCSCNPSILPIEDFQTQFNLTVAEEKIIKHETLPYGRPRVLQKENTICLLSQHQFMSGYSQDILMPLWTSYTVDRNDSFSTEDFSNCLYQDFRIPLSPVHKCSFYKNNTKVSYGELSPPQLNKNSSGIYSEALLTTNIVPMYQSFQVIWRYFHDTLLRKYAEERNGVNVVSGPVFDFDYDGRCDSLENLRQKRRVIRNQEILIPTHFFIVLTSCKDTSQTPLHCENLDTLAFILPHRTDNSESCVHGKHDSSWVEELLMLHRARITDVEHITGLSFYQQRKEPVSDILKLKTHLPTFSQEDNPP2 Amino Acid Sequence (NCBI accession NP_001124335) (SEQ ID NO: 2)MARRSSFQSCQIISLETFAVGVNICLGFTAHRIKRAEGWEEGPPTVLSDSPWTNISGSCKGRCFELQEAGPPDCRCDNLCKSYTSCCHDFDELCLKTARGWECTKDRCGEVRNEENACHCSEDCLARGDCCTNYQVVCKGESHWVDDDCEEIKAAECPAGFVRPPLIIFSVDGFRASYMKKGSKVMPNIEKLRSCGTHSPYMRPVYPTKTFPNLYTLATGLYPESHGIVGNSMYDPVFDATFHLRGREKFNHRWWGGQPLWITATKQGVKAGTFFWSVVIPHERRILTILQWLTLPDHERPSVYAFYSEQPDFSGHKYGPFGPEMTNPLREIDKIVGQLMDGLKQLKLHRCVNVIFVGDHGMEDVTCDRTEFLSNYLTNVDDITLVPGTLGRIRSKESNNAKYDPKAIIANLTCKKPDQHFKPYLKQHLPKRLHYANNRRIEDIHLLVERRWHVARKPLDVYKKPSGKCFFQGDHGEDNKVNSMQTVEVGYGSTFKYKTKVPPFENIELYNVMCDLLGLKPAPNNGTHGSLNHLLRTNTFRPTMPEEVTRPNYPGIMYLQSDFDLGCTCDDKVEPKNKLDELNKRLHTKGSTEAETRKFRGSRNENKENINGNFEPRKERHLLYGRPAVLYRTRYDILYHTDFESGYSEIFLMPLWTSYTVSKQAEVSSVPDHLTSCVRPDVRVSPSFSQNCLAYKNDKQMSYGFLFPPYLSSSPEAKYDAFLVINMVPMYPAFKRVWNYFQRVLVKKYASERNGVNVISGPIFDYDYDGLHDTEDKIKQYVEGSSIPVPTHYYSIITSCLDFTQPADKCDGPLSVSSFILPHRPDNEESCNSSEDESKWVEELMKMHTARVRDIEHLTSLDFFRKTSRSYPEILTLKTYLHTYESEI NPP4 Amino Acid Sequence (NCBI accession AA1118054.1)(SEQ ID NO: 3)MKLLVILLFSGLITGFRSDSSSSLPPKLLLVSFDGFRADYLKNYEEPHLQNFIKEGVLVEHVKNVEITKTFPNHYSIVTGLYEESHGIVANSMYDAVIKKHFSDSNDKDPFWWNEAVPIWVTNQLQENRSSAAAMWPGTDVPIHDTISSYFMNYNSSVSFEERLNNITMWLNNSNPPVTFATLYWEEPDASGHKYGPEDKENMSRVLKKIDDLIGDLVQRLKMLGLWENLNVIITSDHGMTQCSQDRLINLDSCIDHSYYTLIDLSPVAAILPKINRTEVYNKLKNCSPHMNVYLKEDIPNRFYYQHNDRIQPIILVADEGWTIVLNESSQKLGDHGYDNSLPSMHPFLAAHGPAFHKGYKHSTINIVDIYPMMCHILGLKPHPNNGTFGHTKCLLVDQWCINLPEAIAIVIGSLLVLTMLTCLIIIMQNRLSVPRPFSRLQLQEDDDDPLIG (SEQ ID NO: 4)(DSS)_(n), wherein n is an integer ranging from 1 to 10 (SEQ ID NO: 5)(ESS)_(n), wherein n is an integer ranging from 1 to 10 (SEQ ID NO: 6)(RQQ)_(n), wherein n is an integer ranging from 1 to 10 (SEQ ID NO: 7)(KR)_(n), wherein n is an integer ranging from 1 to 10 (SEQ ID NO: 8) R_(m), wherein m is an integer ranging from 1 to 15 (SEQ ID NO: 9)DSSSEEKFLRRIGRFG (SEQ ID NO: 10) EEEEEEEPRGDT (SEQ ID NO: 11)APWHLSSQYSRT (SEQ ID NO: 12) STLPIPHEFSRE (SEQ ID NO: 13) VTKHLNQISQSY(SEQ ID NO: 14) E _(m) wherein m is an integer ranging from 1 to 15NPP121 Amino Acid Sequence (SEQ ID NO: 15)   1 M E R D G C A G G G S R G G E G G R A P  21 R E G P A G N G R D R G R S H A A E A P  41 G D P Q A A A S L L A P M D V G E E P L  61 E K A A R A R T A K D P N T Y K I I S L  81 F T F A V G V N I C L G**F T A G L K P S 101 C A K E V K S C K G R C F E R T F G N C 121 R C D A A C V E L G N C C L D Y Q E I C 141 I E P E H I W T C N K F R C G E K R L T 161 R S L C A C S D D C K D K G D C C I N Y 181 S S V C Q G E K S W V E E P C E S I N E 201 P Q C P A G F E T P P T L L F S L D G F 221 R A E Y L H T W G G L L P V I S K L K K 241 C G T Y T K N M R P V Y P T K T F P N H 261 Y S I V T G L Y P E S H G I I D N K M Y 281 D P K M N A S F S L K S K E K F N P E W 301 Y K G E P I W V T A K Y Q G L K S G T F 321 F W P G S D V E I N G I F P D I Y K M Y 341 N G S V P F E E R I L A V L Q W L Q L P 361 K D E R P H F Y I L Y L E E P D S S G H 381 S Y G P V S S E V I K A L Q R V D G M V 401 G M L M D G L K E L N L H R C L N L I L 421 I S D H G M E Q G S C K K Y I Y L N K Y 441 L G D V K N I K V I Y G P A A R L R P 5 461 D V P D K Y Y S F N Y E G I A R N L S C 481 R E P N Q H F K P Y L K H F L P K R L H 501 F A K S D R I E P L I F Y L D P Q W Q L 521 A L N P S E R K Y C G S G F H G S D N V 541 F S N M Q A L F V G Y G P G F K H G I E 561 A D T F E N I E V Y N L M C D L L N L T 581 P A P N N G T H G S L N H L L K N P V Y 601 T P K H P K E V H P L V Q C P F T R N P 621 R D N L G C S C N P S I L P I E D F Q T 641 Q F N L T V A E E K I I K H E T L P Y G 661 R P R V L Q K E N T I C L L S Q H Q F M 681 S G Y S Q D I L M P L W T S Y T V D R N 701 D S F S T E D F S N C L Y Q D F R I P L 721 S P V H K C S F Y K N N T K V S Y G F L 741 S P P Q L N K N S S G I Y S E A L L T T 761 N I V P M Y Q S F Q V I W R Y F H D T L 781 L R K Y A E E R N G V N V V S G P V F D 801 F D Y D G R C D S L E N L R Q K R R V I 821 R N Q E I L I P T H F F I V L T S C K D 841 T S Q T P L H C E N L D T L A F I L P H 861 R T D N S E S C V H G K H D S S W V E E 881 L L M L H R A R I T D V E H I T G L S F 901 Y Q Q R K E P V S D I L K L K T H L P T  921 F S Q E DSingly Underlined: residues swapped with NPP2residues 1-27 to afford cleavage at transitionposition (**); Doubly Underlined: NPP1 protein (beginning and end).NPP121-Fc Amino Acid Sequence (SEQ ID NO: 16)   1 M E R D G C A G G G S R G G E G G R A P  21 R E G P A G N G R D R G R S H A A E A P  41 G D P Q A A A S L L A P M D V G E E P L  61 E K A A R A R T A K D P N T Y K I I S L  81 F T F A V G V N I C L G **F T A G L K P S 101 C A K E V K S C K G R C F E R T F G N C 121 R C D A A C V E L G N C C L D Y Q E I C 141 I E P E H I W I C N K F R C G E K R L T 161 R S L C A C S D D C K D K G D C C I N Y 181 S S V C Q G E K S W V E E P C E S I N E 201 P Q C P A G F E T P P T L L F S L D G F 221 R A E Y L H T W G G L L P V I S K L K K 241 C G T Y I K N M R P V Y P I K T F P N H 261 Y S I V T G L Y P E S H G I I D N K M Y 281 D P K M N A S F S L K S K E K F N P E W 301 Y K G E P I W V T A K Y Q G L K S G T F 321 F W P G S D V E I N G I F P D I Y K N Y 341 N G S V P F E E R I L A V L Q W L Q L P 361 K D E R P H F Y T L Y L E E P D S S G H 381 S Y G P V S S E V I K A L Q R V D G M V 401 G M L M D G L K E L N L H R C L N L I L 421 I S D H G M E Q G S C K K Y I Y L N K Y 441 L G D V K N I K V I Y G P A A R L R P 5 461 D V P D K Y Y S F N Y E G I A R N L S C 481 R E P N Q H F K P Y L K H F L P K R L H 501 F A K S D R I E P L T F Y L D P Q W Q L 521 A L N P S E R K Y C G S G F H G S D N V 541 F S N M Q A L F V G Y G P G F K H G I E 561 A D I F E N I E V Y N L M C D L L N L I 581 P A P N N G T H G S L N H L L K N P V Y 601 T P K H P K E V H P L V Q C P F T R N P 621 R D N L G C S C N P S I L P I E D F Q T 641 Q F N L T V A E E K I I K H E T L P Y G 661 R P R V L Q K E N T I C L L S Q H Q F M 681 S G Y S Q D I L M P L W I S Y T V D R N 701 D S F S T E D F S N C L Y Q D F R I P L 721 S P V H K C S F Y K N N T K V S Y G F L 741 S P P Q L N K N S S G I Y S E A L L T T 761 N I V P M Y Q S F Q V I W R Y F H D T L 781 L R K Y A E E R N G V N V V S G P V F D 801 F D Y D G R C D S L E N L R Q K R R V I 821 R N Q E I L I P T H F F I V L T S C K D 841 T S Q T P L H C E N L D T L A F I L P H 861 R T D N S E S C V H G K H D S S W V E E 881 L L M L H R A R I T D V E H I T G L S F 901 Y Q Q R K E P V S D I L K L K T H L P T 921 F S Q E D L I N D K T H T C P P C P A P 941 E L L G G P S V F L F P P K P K D T L M 961 I S R T P E V T C V V V D V S H E D P E 981 V K F N W Y V D G V E V H N A K T K P R1001 E E Q Y N S T Y R V V S V L T V L H Q D1021 W L N G K E Y K C K V S N K A L P A P I1041 E K T I S K A K G Q P R E P Q V Y T L P1061 P S R E E M T K N Q V S L T C L V K G F1081 Y P S D I A V E W E S N G Q P E N N Y K1101 T T P P V L D S D G S F F L Y S K L T V1121 D K S R W Q Q G N V F S C S V M H E A L1141 H N H Y T Q K S L S L S P G KSingly Underlined: residues swapped with NPP2residues 1-27 to afford cleavage at transitionposition (**); Doubly Underlined: NPP1 protein(beginning and end); Bold: hIgG1 (Fc) NPP71 Amino Acid Sequence(SEQ ID NO: 17)    1 MRGPAVLLTV ALATLLAPGA GAGLKPSCAK EVKSCKGRCF ERTFGNCRCD  51 AACVELGNCC LDYQETCIEP EHIWTCNKFR CGEKRLTRSL CACSDDCKDK 101 GDCCINYSSV CQGEKSWVEE PCESINEPQC PAGFETPPTL LFSLDGFRAE 151 YLHTWGGLLP VISKLKKCGT YTKNMRPVYP TKTFPNHYSI VTGLYPESHG 201 IIDNKMYDPK MNASFSLKSK EKFNPEWYKG EPIWVTAKYQ GLKSGTFFWP 251 GSDVEINGIF PDIYKMYNGS VPFEERILAV LQWLQLPKDE RPHFYTLYLE 301 EPDSSGHSYG PVSSEVIKAL QRVDGMVGML MDGLKELNLH RCLNLILISD 351 HGMEQGSCKK YIYLNKYLGD VKNIKVIYGP AARLRPSDVP DKYYSFNYEG 401 IARNLSCREP NQHFKPYLKH FLPKRLHFAK SDRIEPLTFY LDPQWQLALN 451 PSERKYCGSG FHGSDNVFSN MQALFVGYGP GFKHGIEADT FENIEVYNLM 501 CDLLNLTPAP NNGTHGSLNH LLKNPVYTPK HPKEVHPLVQ CPFTRNPRDN 551 LGCSCNPSIL PIEDFQTQFN LTVAEEKIIK HETLPYGRPR VLQKENTICL 601 LSQHQFMSGY SQDILMPLWT SYTVDRNDSF STEDFSNCLY QDFRIPLSPV 651 HKCSFYKNNT KVSYGFLSPP QLNKNSSGIY SEALLTTNIV PMYQSFQVIW 701 RYFHDTLLRK YAEERNGVNV VSGPVFDFDY DGRCDSLENL RQKRRVIRNQ 751 EILIPTHFFI VLTSCKDTSQ TPLHCENLDT LAFILPHRTD NSESCVHGKH 801 DSSWVEELLM LHRARITDVE HITGLSFYQQ RKEPVSDILK LKTHLPTFSQ  851  EDSingly Underlined: NPP7; Doubly Underlined: NPP1 protein(beginning and end). NPP71-Fc Amino Acid Sequence (SEQ ID NO: 18)   1 MRGPAVLLTV ALATLLAPGA GA GLKPSCAK EVKSCKGRCF ERTFGNCRCD  51 AACVELGNCC LDYQETCIEP EHIWTCNKFR CGEKRLTRSL CACSDDCKDK 101 GDCCINYSSV CQGEKSWVEE PCESINEPQC PAGFETPPTL LFSLDGFRAE 151 YLHTWGGLLP VISKLKKCGT YTKNMRPVYP TKTFPNHYSI VTGLYPESHG 201 IIDNKMYDPK MNASFSLKSK EKFNPEWYKG EPIWVTAKYQ GLKSGTFFWP 251 GSDVEINGIF PDIYKMYNGS VPFEERILAV LQWLQLPKDE RPHFYTLYLE 301 EPDSSGHSYG PVSSEVIKAL QRVDGMVGML MDGLKELNLH RCLNLILISD 351 HGMEQGSCKK YIYLNKYLGD VKNIKVIYGP AARLRPSDVP DKYYSFNYEG 401 IARNLSCREP NQHFKPYLKH FLPKRLHFAK SDRIEPLTFY LDPQWQLALN 451 PSERKYCGSG FHGSDNVFSN MQALFVGYGP GFKHGIEADT FENIEVYNLM 501 CDLLNLTPAP NNGTHGSLNH LLKNPVYTPK HPKEVHPLVQ CPFTRNPRDN 551 LGCSCNPSIL PIEDFQTQFN LTVAEEKIIK HETLPYGRPR VLQKENTICL 601 LSQHQFMSGY SQDILMPLWT SYTVDRNDSF STEDFSNCLY QDFRIPLSPV 651 HKCSFYKNNT KVSYGFLSPP QLNKNSSGIY SEALLTTNIV PMYQSFQVIW 701 RYFHDTLLRK YAEERNGVNV VSGPVFDFDY DGRCDSLENL RQKRRVIRNQ 751 EILIPTHFFI VLTSCKDTSQ TPLHCENLDT LAFILPHRTD NSESCVHGKH 801 DSSWVEELLM LHRARITDVE HITGLSFYQQ RKEPVSDILK LKTHLPTFSQ 851 EDLINDKTHT CPPCPAPELL GGPSVFLFPP KPKDTLMISR TPEVTCVVVD 901 VSHEDPEVKF NWYVDGVEVH NAKTKPREEQ YNSTYRVVSV LTVLHQDWLN 951 GKEYKCKVSN KALPAPIEKT ISKAKGQPRE PQVYTLPPSR EEMTKNQVSL1001 TCLVKGFYPS DIAVEWESNG QPENNYKTTP PVLDSDGSFF LYSKLTVDKS1051 RWQQGNVFSC SVMHEALHNH YTQKSLSLSP GKSingly Underlined: NPP7; Doubly Underlined: NPP1 protein(beginning and end); Bold: hIgG1 (Fc).(NPP71 lacking NPP1 N-Terminus GLK) Amino Acid Sequence (SEQ ID NO: 19)   1 MRGPAVLLTV ALATLLAPGA GA   PSCAK EVKSCKGRCF ERTFGNCRCD  51 AACVELGNCC LDYQETCIEP EHIWTCNKFR CGEKRLTRSL CACSDDCKDK 101 GDCCINYSSV CQGEKSWVEE PCESINEPQC PAGFETPPTL LFSLDGFRAE 151 YLHTWGGLLP VISKLKKCGT YTKNMRPVYP TKTFPNHYSI VTGLYPESHG 201 IIDNKMYDPK MNASFSLKSK EKFNPEWYKG EPIWVTAKYQ GLKSGTFFWP 251 GSDVEINGIF PDIYKMYNGS VPFEERILAV LQWLQLPKDE RPHFYTLYLE 301 EPDSSGHSYG PVSSEVIKAL QRVDGMVGML MDGLKELNLH RCLNLILISD 351 HGMEQGSCKK YIYLNKYLGD VKNIKVIYGP AARLRPSDVP DKYYSFNYEG 401 IARNLSCREP NQHFKPYLKH FLPKRLHFAK SDRIEPLTFY LDPQWQLALN 451 PSERKYCGSG FHGSDNVFSN MQALFVGYGP GFKHGIEADT FENIEVYNLM 501 CDLLNLTPAP NNGTHGSLNH LLKNPVYTPK HPKEVHPLVQ CPFTRNPRDN 551 LGCSCNPSIL PIEDFQTQFN LTVAEEKIIK HETLPYGRPR VLQKENTICL 601 LSQHQFMSGY SQDILMPLWT SYTVDRNDSF STEDFSNCLY QDFRIPLSPV 651 HKCSFYKNNT KVSYGFLSPP QLNKNSSGIY SEALLTTNIV PMYQSFQVIW 701 RYFHDTLLRK YAEERNGVNV VSGPVFDFDY DGRCDSLENL RQKRRVIRNQ 751 EILIPTHFFI VLTSCKDTSQ TPLHCENLDT LAFILPHRTD NSESCVHGKH 801 DSSWVEELLM LHRARITDVE HITGLSFYQQ RKEPVSDILK LKTHLPTFSQ  851 EDSingly Underlined: NPP7; Doubly Underlined: NPP1 protein(beginning and end) (first 3-aminoacids at the N-terminus of NPP1, GLK, are omitted).(NPP71 lacking NPP1 N-Terminus GLK)-Fc Amino Acid Sequence(SEQ ID NO: 20)   1 MRGPAVLLTV ALATLLAPGA GA   PSCAK EVKSCKGRCF ERTFGNCRCD  51 AACVELGNCC LDYQETCIEP EHIWTCNKFR CGEKRLTRSL CACSDDCKDK 101 GDCCINYSSV CQGEKSWVEE PCESINEPQC PAGFETPPTL LFSLDGFRAE 151 YLHTWGGLLP VISKLKKCGT YTKNMRPVYP TKTFPNHYSI VTGLYPESHG 201 IIDNKMYDPK MNASFSLKSK EKFNPEWYKG EPIWVTAKYQ GLKSGTFFWP 251 GSDVEINGIF PDIYKMYNGS VPFEERILAV LQWLQLPKDE RPHFYTLYLE 301 EPDSSGHSYG PVSSEVIKAL QRVDGMVGML MDGLKELNLH RCLNLILISD 351 HGMEQGSCKK YIYLNKYLGD VKNIKVIYGP AARLRPSDVP DKYYSFNYEG 401 IARNLSCREP NQHFKPYLKH FLPKRLHFAK SDRIEPLTFY LDPQWQLALN 451 PSERKYCGSG FHGSDNVFSN MQALFVGYGP GFKHGIEADT FENIEVYNLM 501 CDLLNLTPAP NNGTHGSLNH LLKNPVYTPK HPKEVHPLVQ CPFTRNPRDN 551 LGCSCNPSIL PIEDFQTQFN LTVAEEKIIK HETLPYGRPR VLQKENTICL 601 LSQHQFMSGY SQDILMPLWT SYTVDRNDSF STEDFSNCLY QDFRIPLSPV 651 HKCSFYKNNT KVSYGFLSPP QLNKNSSGIY SEALLTTNIV PMYQSFQVIW 701 RYFHDTLLRK YAEERNGVNV VSGPVFDFDY DGRCDSLENL RQKRRVIRNQ 751 EILIPTHFFI VLTSCKDTSQ TPLHCENLDT LAFILPHRTD NSESCVHGKH 801 DSSWVEELLM LHRARITDVE HITGLSFYQQ RKEPVSDILK LKTHLPTESQ 851 EDLINDKTHT CPPCPAPELL GGPSVFLFPP KPKDTLMISR TPEVTCVVVD 901 VSHEDPEVKF NWYVDGVEVH NAKTKPREEQ YNSTYRVVSV LTVLHQDWLN 951 GKEYKCKVSN KALPAPIEKT ISKAKGQPRE PQVYTLPPSR EEMTKNQVSL1001 TCLVKGFYPS DIAVEWESNG QPENNYKTTP PVLDSDGSFF LYSKLTVDKS1051 RWQQGNVFSC SVMHEALHNH YTQKSLSLSP GKSingly Underlined: NPP7; Doubly Underlined: NPP1 protein(beginning and end) (first 3-amino acids at the N-terminusof NPP1 are omitted); Bold: hIgG1 (Fc). NPP121-ALB Amino Acid Sequence(SEQ ID NO: 21)

LFTFAVGVNICLG**FTAGLKPSCAKEVKSCKGRCFERTFGNCRCDAACVELGNCCLDYQETCIEPEHIWTCNKFRCGEKRLTRSLCACSDDCKDKGDCCINYSSVCQGEKSWVEEPCESINEPQCPAGFETPPTLLFSLDGFRAEYLHTWGGLLPVISKLKKCGTYTKNMRPVYPTKTFPNHYSIVTGLYPESHGIIDNKMYDPKMNASFSLKSKEKFNPEWYKGEPIWVTAKYQGLKSGTFFWPGSDVEINGIFPDIYKMYNGSVPFEERILAVLQWLQLPKDERPHFYTLYLEEPDSSGHSYGPVSSEVIKALQRVDGMVGMLMDGLKELNLHRCLNLILISDHGMEQGSCKKYTYLNKYLGDVKNIKVIYGPAARLRPSDVPDKYYSFNYEGIARNLSCREPNQHFKPYLKHFLPKRLHFAKSDRIEPLTFYLDPQWQLALNPSERKYCGSGFHGSDNVFSNMQALFVGYGPGFKHGIEADTFENIEVYNLMCDLLNLTPAPNNGTHGSLNHLLKNPVYTPKHPKEVHPLVQCPFTRNPRDNLGCSCNPSILPIEDFQTQFNLTVAEEKIIKHETLPYGRPRVLQKENTICLLSQHQEMSGYSQDILMPLWTSYTVDRNDSFSTEDFSNCLYQDFRIPLSPVHKCSFYKNNTKVSYGFLSPPQLNKNSSGIYSEALLTTNIVPMYQSFQVIWRYFHDTLLRKYAEERNGVNVVSGPVFDFDYDGRCDSLENLRQKRRVIRNQEILIPTHFFIVLTSCKDTSQTPLHCENLDTLAFILPHRTDNSESCVHGKHDSSWVEELLMLHRARITDVEHITGLSFYQQRKEPVSDILKLKTHLPTESQED RSGSGGS MKWVTFLLLLFVSGSAFSRGVFRREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDFAKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMCTSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMKCSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSKLQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRLAKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLVEAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVPKEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPNLVTRCKDALARSWSHPQFEK Bold Italics: NPP1 cytoplasmic and transmembrane;Singly Underlined: Swapped residues with NPP2 residues1-27 to give cleavage at transition position (**);Doubly Underlined: NPP1 transmembrane; Plain: NPP1Extracellular Domain; Bold Underlined: Linker; Bold: Albumin(NPP71 lacking NPP1 N-Terminus GLK)-ALB Amino Acid Sequence(SEQ ID NO: 22)MRGPAVLLTVALATLLAPGAGAPSCAKEVKSCKGRCFERTFGNCRCDAACVELGNCCLDYQETCIEPEHIWTCNKFRCGEKRLTRSLCACSDDCKDKGDCCINYSSVCQGEKSWVEEPCESINEPQCPAGFETPPTLLFSLDGFRAEYLHTWGGLLPVTSKLKKCGTYTKNMRPVYPTKTFPNHYSIVTGLYPESHGIIDNKMYDPKMNASFSLKSKEKFNPEWYKGEPIWVTAKYQGLKSGTFFWPGSDVEINGIFPDIYKMYNGSVPFEERILAVLQWLQLPKDERPHFYTLYLEEPDSSGHSYGPVSSEVIKALQRVDGMVGMLMDGLKELNLHRCLNLILISDHGMEQGSCKKYIYLNKYLGDVKNIKVIYGPAARLRPSDVPDKYYSFNYEGIARNLSCREPNQHFKPYLKHFLPKRLHFAKSDRIEPLTFYLDPQWQLALNPSERKYCGSGEHGSDNVESNMQALFVGYGPGEKHGTEADTFENTEVYNLMCDLLNLTPAPNNGTHGSLNHLLKNPVYTPKHPKEVHPLVQCPFTRNPRDNLGCSCNPSILPIEDFQTQFNLTVAEEKIIKHETLPYGRPRVLQKENTICLLSQHQFMSGYSQDILMPLWTSYTVDRNDSFSTEDFSNCLYQDFRIPLSPVHKCSFYKNNTKVSYGFLSPPQLNKNSSGIYSEALLTTNIVPMYQSFQVIWRYFHDTLLRKYAEERNGVNVVSGPVFDFDYDGRCDSLENLRQKRRVIRNQEILIPTHFFIVLTSCKDTSQTPLHCENLDTLAFILPHRTDNSESCVHGKHDSSWVEELLMLHRARITDVEHITGLSFYQQRKEPVSDILKLKTHLPTFSQEDRSGSGGS MKWVTFLLLLEVSGSAFSRGVERREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDFAKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMCTSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMKCSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSKLQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRLAKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLVEAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVPKEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPNLVTRCKDALARSWSHPQFEKDoubly Underlined: NPP7; Plain Text: NPP1; Bold: spacer sequence;Singly Underlined: albumin (SEQ ID NO: 23) IISLFTFAVGVNICLGFTANPP51 Amino Acid Sequence (SEQ ID NO: 24)MTSKFLLVSFILAALSLSTIFSLQPSCAKEVKSCKGRCFERTFSNCRCDAACVSLGNCCLDFQETCVEPTHIWTCNKFRCGEKRLSREVCSCADDCKTHNDCCINYSSVCQDKKSWVEETCESIDTPECPAEFESPPTLLFSLDGFRAEYLHTWGGLLPVISKLKNCGTYTKNMRPMYPTKTFPNHYSIVTGLYPESHGIIDNKMYDPKMNASFSLKSKEKFNPLWYKGQPIWVTANHQEVKSGTYFWPGSDVEIDGILPDIYKVYNGSVPFEERILAVLEWLQLPSHERPHFYTLYLEEPDSSGHSHGPVSSEVIKALQKVDRLVGMLMDGLKDLGLDKCLNLILISDHGMEQGSCKKYVYLNKYLGDVNNVKVVYGPAARLRPTDVPETYYSFNYEALAKNLSCREPNQHFRPYLKPFLPKRLHFAKSDRIEPLIFYLDPQWQLALNPSERKYCGSGEHGSDNLFSNMQALFIGYGPAFKHGAEVDSFENIEVYNLMCDLLGLIPAPNNGSHGSLNHLLKKPIYNPSHPKEEGFLSQCPIKSTSNDLGCTCDPWIVPIKDFEKQLNLTTEDVDDIYHMTVPYGRPRILLKQHRVCLLQQQQFLTGYSLDLLMPLWASYTFLSNDQFSRDDFSNCLYQDLRIPLSPVHKCSYYKSNSKLSYGFLTPPRLNRVSNHIYSEALLTSNIVPMYQSFQVIWHYLHDTLLQRYAHERNGINVVSGPVEDFDYDGRYDSLEILKQNSRVIRSQEILIPTHFFIVLTSCKQLSETPLECSALESSAYILPHRPDNIESCTHGKRESSWVEELLTLHRARVTDVELITGLSFYQDRQESVSELLRLKTHLPIFSQEDUnderlined: NPP5; Plain: NPP1 NPP51-ALB Amino Acid Sequence(SEQ ID NO: 25)MTSKFLLVSFILAALSLSTIESLQPSCAKEVKSCKGRCFERTFSNCRCDAACVSLGNCCLDFQETCVEPTHIWTCNKFRCGEKRLSREVCSCADDCKTHNDCCINYSSVCQDKKSWVEETCESIDTPECPAEFESPPTLLFSLDGFRAEYLHTWGGLLPVISKLKNCGTYTKNMRPMYPTKTFPNHYSIVTGLYPESHGIIDNKMYDPKMNASFSLKSKEKFNPLWYKGQPIWVTANHQEVKSGTYFWPGSDVEIDGILPDIYKVYNGSVPFEERILAVLEWLQLPSHERPHFYTLYLEEPDSSGHSHGPVSSEVIKALQKVDRLVGMLMDGLKDLGLDKCLNLILISDHGMEQGSCKKYVYLNKYLGDVNNVKVVYGPAARLRPTDVPETYYSFNYEALAKNLSCREPNQHFRPYLKPFLPKRLHFAKSDRIEPLIFYLDPQWQLALNPSERKYCGSGEHGSDNLFSNMQALFIGYGPAFKHGAEVDSFENIEVYNLMCDLLGLIPAPNNGSHGSLNHLLKKPIYNPSHPKEEGFLSQCPIKSTSNDLGCTCDPWIVPIKDFEKQLNLTTEDVDDIYHMTVPYGRPRILLKQHRVCLLQQQQFLTGYSLDLLMPLWASYTFLSNDQFSRDDFSNCLYQDLRIPLSPVHKCSYYKSNSKLSYGFLTPPRLNRVSNHIYSEALLTSNIVPMYQSFQVIWHYLHDTLLQRYAHERNGINVVSGPVFDFDYDGRYDSLEILKQNSRVIRSQEILIPTHFFIVLTSCKQLSETPLECSALESSAYILPHRPDNIESCTHGKRESSWVEELLTLHRARVTDVELITGLSFYQDRQESVSELLRLKTHLPIFSQEDGGSGGS MKWVTFLLLLFVSGSAFSRGVERREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDFAKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMCTSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMKCSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSKLQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRLAKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLVEAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVPKEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPNLVTRCKDALARSWSHPQFEKDoubly Underlined: NPP5; Plain: NPP1; Bold: Spacer; SinglyUnderlined: Albumin Human IgG Fe domain, Fc (SEQ ID NO: 26)DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFELYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK ALB (SEQ ID NO: 27)MKWVTFLLLLEVSGSAFSRGVERREAHKSEIAHRYNDLGEQHFKGLVLIAFSQYLQKCSYDEHAKLVQEVTDFAKTCVADESAANCDKSLHTLFGDKLCAIPNLRENYGELADCCTKQEPERNECFLQHKDDNPSLPPFERPEAEAMCTSFKENPTTFMGHYLHEVARRHPYFYAPELLYYAEQYNEILTQCCAEADKESCLTPKLDGVKEKALVSSVRQRMKCSSMQKFGERAFKAWAVARLSQTFPNADFAEITKLATDLTKVNKECCHGDLLECADDRAELAKYMCENQATISSKLQTCCDKPLLKKAHCLSEVEHDTMPADLPAIAADFVEDQEVCKNYAEAKDVFLGTFLYEYSRRHPDYSVSLLLRLAKKYEATLEKCCAEANPPACYGTVLAEFQPLVEEPKNLVKTNCDLYEKLGEYGFQNAILVRYTQKAPQVSTPTLVEAARNLGRVGTKCCTLPEDQRLPCVEDYLSAILNRVCLLHEKTPVSEHVTKCCSGSLVERRPCFSALTVDETYVPKEFKAETFTFHSDICTLPEKEKQIKKQTALAELVKHKPKATAEQLKTVMDDFAQFLDTCCKAADKDTCFSTEGPNLVTRCKDALARSWSHPQFEK (SEQ ID NO: 28) LIN (SEQ ID NO: 29) GGSGGS(SEQ ID NO: 30) RSGSGGS

Example 1: ENPP1-asj PXE Mouse Model

Certain polypeptides of the invention (such as ENPP1-Fc) were tested inmouse models of PXE and osteoarthritis (OA). The PXE mice present theloss of function mutation in the multi-pass membrane transporter ABCC6,in a similar fashion to humans with PXE. ANK mice were used as amammalian model for OA.

Heterozygous ENPP1-asj/+ breeding pairs were maintained on the“acceleration diet” (TD00.442, Harlan Laboratories, Madison Wis.)throughout the entire experiment to generate ENPP1-WT and ENPP1-asj/asjsibling pairs that had been exposed to the acceleration diet in utero.Liters were genotyped on day 8 and weaned at day 21. Following weaning,sibling pairs were divided into experimental cohorts and allexperimental animals were maintained on the acceleration diet throughcompletion of the study. Selected polypeptides of the invention weresadministered to study animals, as described herein, and bones areanalyzed.

As illustrated in FIG. 7, both PXE and ANK mice initially have low PPi,a biomarker that is reported in the literature to account for thepathogenesis of PXE (Jansen, et al., 2014, Arterioscler. Thromb. Vasc.Biol. 34:1985-1989).

Two PXE mice were dosed for one week with ENPP1-Fc, and the mean plasmaPPi in these animals increased to about 4 μM. This indicates thatadministration of the polypeptides of the invention to mammals raisestheir extracellular levels of PPi and treats PXE.

The polypeptide's ability to elevate PPi was not expected, because thebiological mechanism for low PPi was thought to be associated with lowATP concentrations (Jansen, et al., 2013, PNAS USA 110(50):20206-20211).In fact, it was proposed in the prior art that correction of plasma PPiin PXE is sufficient to treat the disease (Jansen, et al., 2013, PNASU.S.A. 110(50):20206-20211). Based on the prior art at the time of theinvention, one skilled in the art would contemplate that ENPP1 enzyme isnot able to generate PPi in the setting of PXE due to lack of sufficientsubstrate in the extracellular space. As demonstrated herein, this isclearly not the case.

Example 2

When fed an acceleration diet, the daily weights of ENPP1-asj/asj micediverged from WT siblings pairs at day 26, when the ENPP1-asj/asj miceexperienced a “failure to thrive” event and began to lose weight (FIG.1A). After day 26 the ENPP1-asj/asj animals displayed progressivestiffness and reductions in physical activity. All of the ENPP1-asj/asjanimals died between days 35-71, with a median lifespan of 58 days (FIG.1G). The presence of calcifications in ENPP1-asj/asj and ENPP1-WT micewas evaluated post mortem by micro-CT scans and histologic sectionstaken from the heart, aorta, and kidneys. Approximately one-third of theENPP1-asj/asj mice had visible calcifications in their hearts, andtwo-thirds had visible calcifications in their aortas, by micro-CTimaging (Table 2). These percentages increased to 100% upon histologicexamination, which also showed that many of the animals had dramaticnearly circumferential calcifications in their aortic walls (FIGS.1D-1E). Histologic examination also revealed that 100% of the coronaryarteries possessed arterial wall calcifications, and that 70% of theanimals had focal or confluent areas of myocardial necrosis consistentwith myocardial infarction (FIGS. 1F-1G). Conversely, the ENPP1-WT micedisplayed none of these abnormalities. These findings demonstrate thatthe animal model recapitulates GACI in humans, which is characterized byprominent calcifications of the large and medium sized arteries and acardiac demise.

To produce soluble, recombinant ENPP1 for in vivo use, ENPP1 was fusedto the Fc domain of IgG1 (hereafter referred to as ENPP1-Fc, FIG. 2B)and the fusion protein was expressed in stable mammalian (HEK293) celllines. The combined effect of switching protein expression from insectcells to mammalian cells and fusion of ENPP1 to the Fc domain of IgG1altered the Michaelis Menton kinetics by increasing the affinity ofENPP1 for ATP substrate by over two orders of magnitude, while alsoreducing the K_(cat) by a factor of 3-4 (FIGS. 2C-2E). The activity ofENPP1-Fc was noted to diminish over a 30 day period when stored at 4° C.but the enzyme could be frozen at −80° C. and retain nearly completeactivity upon thawing (FIG. 2C). The enzyme was therefore stored as afrozen stock solution after purification until needed.

Following purification, ENPP1-Fc was dialyzed into PBS supplemented withZn and Mg (PBS_(plus)) concentrated to between 5 and 7 mg/ml, and frozenat −80° C. in aliquots of 200-500 μl. Aliquots were thawed immediatelyprior to use and the specific activity of the solution was adjusted to31.25 au/ml (or about 0.7 mg/ml depending on the preparation) bydilution in PBS_(plus).

Dosing was performed according to activity units (au) per Kg animalweight to account for variations in specific activity in differentprotein preparations. The specific activity of the enzyme varied witheach protein preparation, and because the clinical response was noted tobe highly dependent on enzyme specific activity, protein preparationswith specific activities of less than 40 au/mg were rejected. Toestablish initial dosing levels for the proof of concept study, doseescalation trials were performed in limited numbers of animals (1-2 perdose level). While both the human and mouse version ENPP1 was used inthe dose escalation trials, the proof of concept study was performedwith the mouse isoform of ENPP1-Fc (mENPP1-Fc). ENPP1-asj/asj mice weredosed daily on the 14^(th) day of life with subcutaneous injections ofmENPP1-Fc and weekly with intra-peritoneal (LP.) injections of GK 1.5,the latter added to minimize immune rejection of recombinant protein.Subcutaneous doses of mEnpp1-Fc at 500 au/Kg qD demonstrated a strongearly response in weight with an absence of the observed “failure tothrive” crisis observed in undosed ENPP1-asj/asj animals.

Based on the results of the dose escalation trials, a cohort of 8NPP1-asj/asj animals was dosed with mNPP1-Fc at 500 au/Kg qD and weeklyIP injections with GK1.5 (FIG. 3). A control group (NPP1-WT+vehicle andNPP1-asj/asj+vehicle) was dosed daily with vehicle and weekly with GK1.5in an identical manner as the dosed cohort, and the study duration wasshortened to 55 days. All 8 treated ENPP1-asj/asj animals survived thefull 55 days of the trial, with a dramatic clinical response observed intreated, while the median life span of the untreated NPP1 asj/asjanimals decreased from 58 days to 37 days in the therapeutic trial,perhaps resulting from the weekly IP injections of the GK1.5immunosuppressive. The untreated ENPP1-asj/asj animals also allexperienced a failure to thrive crisis day 26, characterized by weightloss and mobility restriction progressing variably to paralysis anddeath over the next 30 days. All but one untreated ENPP1-asj/asj animalexpired over the 55 day trial, while in contrast all treatedENPP1-asj/asj mice gained weight comparable to the ENPP1-WT mice anddisplayed no signs of reduced mobility or stiffness.

At the conclusion of the study, 100% of the ENPP1-asj/asj mice treatedwith vehicle displayed calcifications in their hearts, aortas, andcoronary arteries, and 77% of the animals displayed histologic evidenceof myocardial infraction (Table 1). In most cases this took the form ofsmall areas of myocardial cell necrosis and drop out in the vicinity ofthe cardiac calcifications (FIGS. 3C-3D, FIGS. 4C-4E), but in twoanimals (22%) there were large, full thickness myocardial infarctions inthe free wall of the right ventricle (FIGS. 4C-4D). Myocardial fibrosisin myocardial tissue adjacent to coronary artery calcifications was acommon finding (FIG. 4E), illustrating that ischemia from coronaryartery calcification likely accounts for the myocardial disease. Incontrast, none of the ENPP1-asj/asj animals treated with ENPP1-Fcdisplayed cardiac, arterial, or aortic calcification on histology orpost-mortem micro-CT (Table 1, and FIGS. 3D and 4D).

In addition to survival, daily animal weights, and terminal histology,treatment response was also assessed via post-mortem high resolutionmicro-CT scans to image vascular calcifications, plasma [PPi]concentrations, and Tc99 PPi (^(99m)PYP) uptake (FIG. 5 and Table 1).The biochemical and physiologic response was complete as measured by allof these parameters. None of the WT or treated ENPP1-asj/asj animalswere noted to possess any vascular calcifications via micro-CT, incontrast to the dramatic calcifications noted in the aortas, coronaryarteries, and hearts of the untreated ENPP1-asj/asj cohort (FIG. 5A. Inaddition, serum PPi concentrations of treated ENPP1-asj/asj animals wereelevated above WT animals (about 30 μM in the treated ENPP1-asj/asj vs.about 10 μM in WT), and well above untreated ENPP1-asj/asj levels (<0.5μM) (FIG. 5B). In addition, serum PPi concentrations of treatedENPP1-asj/asj animals (about 30 μM) were elevated well above untreatedENPP1-asj/asj levels (<0.5 μM), and above that of WT animals (about 10μM) (FIG. 5B).

^(99m)PYP, an imaging agent typically employed in cardiac imaging andbone remodeling, was used as a marker for treatment response because onewould expect that ^(99m)PYP uptake in animals lacking functional ENPP1should be increased as they would be expected to have reduce plasma[PPi] and more ‘open’ PPi binding sites at sites of ectopicmineralization. To test this hypothesis, in vivo ^(99m)PYP imaging wasperformed weekly in ENPP1-WT and undosed ENPP1-asj/asj animals to detectdifferences in PYP uptake between the sibling pairs (FIGS. 5C-5D).Analysis of ^(99m)PYP uptake was limited to the head, which is comprisedof both enchondral bone (skull) and soft tissue (vibrissae), which areknown sites of ectopic calcification in mouse models of this GACI. Inaddition, the analysis was limited to the head to simplify datacollection, as the head does not overlap with internal organs showingtransient ^(99m)PYP uptake (such as the bladder, heart, and diaphragm)during the 180° camera rotation that occurs during data collection.

Weekly serial imaging of ENPP1-WT and untreated ENPP1-asj/asj animalsdemonstrated that the percent uptake of the injected dose of ^(99m)PYPin skulls was greater in ENPP1-asj/asj animals than in ENPP1-WT animalsand changes in ^(99m)PYP uptake within experimental groups did not varysignificantly over the course of the study (FIGS. 5C-5D). ^(99m)PYPUptake in treated and untreated ENPP1-asj/asj animals was compared attwo time points −days 30-35 and at the completion of the study (days50-65). Comparison of these experimental groups demonstrates thatENPP1-Fc treatment returned ^(99m)PYP uptake in GACI mice to WT levels(FIGS. 5E-5F), suggesting that ENPP1-Fc treatment is able to abrogateunregulated tissue and skull mineralization in ENPP1-asj/asj mice bysaturating open PPi binding sites with ‘cold’ PPi, which presumablyoriginates from increased plasma PPi concentrations induced by thetherapeutic.

TABLE 1 Cardiovascular Pathology, Proof of Concept Study WT + asj/asj +asj/asj + Vehicle vehicle mENPP1-Fc Calcifications Heart 0/0 55%/100%0/0 (CT/Histology) Calcifications Aorta 0/0 66%/100% 0/0 (CT/Histology)Calcifications in 0/0 43%/100% 0/0 Coronary Arteries (CT/histology) %myocardial 0/0 77% 0 infarction (Histology)

TABLE 2 Cardiovascular Pathology, Natural History Study WT asj/asj %Calcifications in heart 0/0 37%/100% (CT/histology) Calcifications inAorta 0/0 62%/100% (CT/histology) Calcifications in Coronary 0/0 100%Arteries (Histology) % myocardial infarction 0 70% (Histology)

Example 3: Expression of Albumin Fusion Protein

Human serum albumin (HSA), a protein of 585 amino acids, is responsiblefor a significant proportion of the osmotic pressure of serum and alsofunctions as a carrier of endogenous and exogenous ligands. At present,HSA for clinical use is produced by extraction from human blood.Production of recombinant HSA (rHSA) in microorganisms has beendisclosed in EP 0 330 451 and EP 0 361 991.

The role of albumin as a carrier molecule and its inert nature aredesirable properties for use as a stabilizer and transporter ofpolypeptides. Use of albumin as a component of a fusion protein forstabilizing other proteins has been disclosed in WO 93/15199, WO93/15200, and EP 0 413 622. The use of N-terminal fragments of HSA forfusions to polypeptides has also been disclosed (EP 0 399 666). Fusionto the polypeptide is achieved by genetic manipulation, such that theDNA coding for HSA, or a fragment thereof, is joined to the DNA codingfor the polypeptide. A suitable host is then transformed or transfectedwith the fused nucleotide sequences, so arranged on a suitable plasmidas to express a fusion polypeptide. Nomura, et al., 1995, Biosci.Biotechnol. Biochem. 59(3):532-4 attempted to express humanapolipoprotein E in S. cerevisae as a fusion protein with HSA orfragments of HSA, using the HSA pre-sequence to direct secretion. Whilstfusion to full length HSA resulted in the secretion of low levels of theprotein into the medium (maximum yield of 6.3 mg per liter), fusion toHSA (1-198) or HSA (1-390) did not result in secretion into the medium.

The human serum albumin may be a variant of normal HSA (termedhereinafter “HSA”). As used herein, “variants” include insertions,deletions and substitutions, either conservative or non-conservative,where such changes do not, substantially alter one or more of theoncotic, useful ligand-binding and non-immunogenic properties ofalbumin. In particular, “variants” include naturally-occurringpolymorphic variants of human albumin and fragments of human albumin,for example those fragments disclosed in EP 0 322 094 (namely HA (1-n),where n is 369 to 419). The albumin or growth hormone (GH) may be fromany vertebrate, especially any mammal, for example human, cow, sheep,pig, hen or salmon. The albumin and GH parts of the fusion may be fromdiffering animals.

By “conservative substitutions” is intended swaps within groups such asGly/Ala; Val/Ile/Leu; Asp/Glu; Asn/Gln; Ser/Thr; Lys/Arg; and Phe/Tyr.The variant usually has at least 75% (such as at least 80%, 90%, 95% or99%) sequence identity with a length of normal HSA that is the samelength as the variant and that is more identical thereto than any otherlength of normal HSA, once the allowance is made for deletions andinsertions as is customary in this art. Generally speaking, an HSAvariant is at least 100 amino acids long, in some embodiments at least150 amino acids long. The HSA variant may consist of or comprise atleast one whole domain of HSA, for example domains 1 (1-194), 2(195-387), 3 (388-585), 1+2 (1-387), 2+3 (195-585) or 1+3 (1-194,+388-585). Each domain is itself made up of two homologous subdomainsnamely 1-105, 120-194, 195-291, 316-387, 388-491 and 512-585, withflexible inter-subdomain linker regions comprising residues Lys106 toGlu199, Glu292 to Val315 and Glu492 to Ala511. In some embodiments, theHSA part of the NPP1 fusion comprises at least one subdomain or domainof HA or conservative modifications thereof.

Many expression systems are known, including bacteria (for example E.coli and Bacillus subtilis), yeasts (for example Saccharomycescerevisiae, Kluyveromyces lactis and Pichia pastoris), filamentous fungi(for example Aspergillus), plant cells, animal cells and insect cells.

The desired protein can be produced in conventional ways, for examplefrom a coding sequence inserted in the host chromosome or on a freeplasmid.

The yeasts can be transformed with a coding sequence for the desiredprotein in any of the usual ways, for example electroporation. Methodsfor transformation of yeast by electroporation are disclosed in Becker &Guarente, 1990, Methods Enzymol. 194:182. Successfully transformedcells, i.e., cells that contain a DNA construct of the presentinvention, can be identified by well-known techniques. For example,cells resulting from the introduction of an expression construct can begrown to produce the desired polypeptide. Cells can be harvested andlysed and their DNA content examined for the presence of the DNA using amethod, such as that described by Southern, 1975, J. Mol. Biol. 98:503and/or Berent, et al., 1985, Biotech 3:208. Alternatively, the presenceof the protein in the supernatant can be detected using antibodies.

Useful yeast plasmid vectors include pRS403-406 and pRS413-416 and aregenerally available from Stratagene Cloning Systems, La Jolla, Calif.,USA. Plasmids pRS403, pRS404, pRS405 and pRS406 are Yeast Integratingplasmids (YIps) and incorporate the yeast selectable markers HIS3, TRP1,LEU2 and URA3. Plasmids pRS413-416 are Yeast Centromere plasmids (YCps).

A variety of methods have been developed to operably link DNA to vectorsvia complementary cohesive termini. For instance, complementaryhomopolymer tracts can be added to the DNA segment to be inserted to thevector DNA. The vector and DNA segment are then joined by hydrogenbonding between the complementary homopolymeric tails to formrecombinant DNA molecules.

Synthetic linkers containing one or more restriction sites provide analternative method of joining the DNA segment to vectors. The DNAsegment, generated by endonuclease restriction digestion, is treatedwith bacteriophage T4 DNA polymerase or E. coli DNA polymerase I, whichare enzymes that remove protruding, 3′-single-stranded termini withtheir 3′-5′-exonucleolytic activities, and fill in recessed 3′-ends withtheir polymerizing activities.

The combination of these activities thus generates blunt-ended DNAsegments. The blunt-ended segments are then incubated with a large molarexcess of linker molecules in the presence of an enzyme that is able tocatalyze the ligation of blunt-ended DNA molecules, such asbacteriophage T4 DNA ligase. Thus, the products of the reaction are DNAsegments carrying polymeric linker sequences at their ends. These DNAsegments are then cleaved with the appropriate restriction enzyme andligated to an expression vector that has been cleaved with an enzymethat produces termini compatible with those of the DNA segment.

Synthetic linkers containing a variety of restriction endonuclease sitesare commercially available from a number of sources includingInternational Biotechnologies Inc, New Haven, Conn., USA.

A desirable way to modify the DNA in accordance with the invention, if,for example HA variants are to be prepared, is to use the polymerasechain reaction as disclosed by Saiki, et al., 1988, Science 239:487-491.In this method the DNA to be enzymatically amplified is flanked by twospecific oligonucleotide primers that themselves become incorporatedinto the amplified DNA. The specific primers may contain restrictionendonuclease recognition sites which can be used for cloning intoexpression vectors using methods known in the art.

ENPP1-ALB Design:

Modified, human and mouse NPP1 (Human: NCBI accession NP_006199; Mouse:NCBI accession NP_03839) modified to express soluble, recombinantprotein is fused to human serum albumin (HSA) by sub cloning into pFUSEplasmids (InvivoGen, San Diego Calif.), respectively.

Protein Production:

Shaking flasks: Stable transfections of the ENPP1-ALB are established inHEK293 cells under zeocin selection, and adherent HEK293 cells can beadapted for suspension growth. Adapted cells are used to seed liquidculture growths in FreeStyle medium (Gibco #12338-018) in shaker flasksat 37° C. and 5% CO₂, agitated at 120 rpm with high humidity. Theculture is gradually expanded to the desired target volume and thenmaintained for another 12 days to accumulate extracellular protein.During the maintenance phase, cultures are supplemented with CDEfficientFeed C AGT (Gibco #A13275-05) to enhance protein production.

Bioreactor: Cells are propagated in a 10 liter bioreactor equipped withdissolved oxygen and pH control. Dissolved oxygen is kept at 40% airsaturation by supplying the culture with mixture of air and oxygen notexceeding 3 liter per minute at an agitation rate of 80 RPM. pH iascontrolled at 7.4 by sparging CO₂ when the pH ise higher than 7.4.Culture growth is followed by measuring cell number, cell viability,glucose and lactate concentrations.

Protein Purification:

The liquid cultures are centrifuged at 4300×g for 15 min and thesupernatants are filtered through a 0.2 μm membrane and concentrated viatangential flow using a Pellicon®3 0.11 m2 Ultracell® 30 kD cassette(Millipore, Billerica Mass.). The concentrated supernatant is loadedonto a protein-AG column and can be eluted with a buffer comprising 50mM Sodium Citrate, 150 mM NaCl, 3 mM ZnCl₂, 3 mM CaCl₂, pH=3.5.Fractions containing enzymatic activity are pooled and dialyzed againstIX PBS buffer pH 7.4, 11 μM ZnCl₂, 20 μM CaCl₂, then concentrated to 6mg/ml, distributed into small aliquots and stored at −80° C.

The resulting protein samples are tested with Pierce LAL ChromogenicEndotoxin Quantitation Kit (cat. 88282) to verify that all are free ofendotoxin.

Enzymology

The NPP1-albumin fusion protein after purification are characterizedfollowing the experimental protocols discussed in Examples 1 and 2,described elsewhere herein.

The disclosures of each and every patent, patent application, andpublication cited herein are hereby incorporated herein by reference intheir entirety. While this invention has been disclosed with referenceto specific embodiments, it is apparent that other embodiments andvariations of this invention may be devised by others skilled in the artwithout departing from the true spirit and scope of the invention. Theappended claims are intended to be construed to include all suchembodiments and equivalent variations.

1. A compound of formula (I), or a salt thereof:PROTEIN-Z-DOMAIN-X—Y  (I), wherein in (I): PROTEIN is selected from thegroup consisting of SEQ ID NO:15, SEQ ID NO:17, SEQ ID NO:19, and SEQ IDNO:24; DOMAIN is selected from the group consisting of a human IgG Fcdomain (Fc), human serum albumin protein (ALB) and fragment thereof; Xand Z are independently absent or a polypeptide comprising 1-20 aminoacids; and, Y is absent or is a sequence selected from the groupconsisting of: (DSS)_(n) (SEQ ID NO:4), (ESS)_(n) (SEQ ID NO:5),(RQQ)_(n) (SEQ ID NO:6), (KR)_(n) (SEQ ID NO:7), R_(m) (SEQ ID NO:8),DSSSEEKFLRRIGRFG (SEQ ID NO:9), EEEEEEEPRGDT (SEQ ID NO:10),APWHLSSQYSRT (SEQ ID NO:11), STLPIPHEFSRE (SEQ ID NO:12), VTKHLNQISQSY(SEQ ID NO:13), and E_(m) (SEQ ID NO:14), wherein m is an integerranging from 1 to 15, and wherein n is an integer ranging from 1 to 10.2. The compound of claim 1, wherein DOMAIN is a Fc or fragment thereof.3. The compound of claim 1, wherein DOMAIN is an ALB or fragmentthereof.
 4. The compound of claim 1, wherein Y is absent and thecompound lacks a negatively-charged bone-targeting sequence.
 5. Thecompound of claim 1, wherein the PROTEIN has a mutation in at least oneposition selected from the group consisting of Ser 532, Tyr 529, Tyr451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relativeto SEQ ID NO:
 1. 6. The compound of claim 1, wherein the nuclease domainof the PROTEIN or mutant thereof is absent.
 7. The compound of claim 1,wherein the nuclease domain from about residue 524 to about residue 885relative to SEQ ID NO:1 is absent in the PROTEIN or mutant thereof. 8.The compound of claim 1, wherein a segment of the extracellular regionof NNP2 containing a furin or signal peptide cleavage site is, or isnot, substituted into the PROTEIN or mutant thereof.
 9. The compound ofclaim 1, wherein DOMAIN is a Fc or fragment thereof, and whereinPROTEIN-Z-DOMAIN comprises (SEQ ID NO:15)-Z-(Fc or fragment thereof),(SEQ ID NO:17)-Z-(Fc or fragment thereof), (SEQ ID NO:19)-Z-(Fc orfragment thereof), (SEQ ID NO:24)-Z-(Fc or fragment thereof), or amutant thereof comprising at least one mutation in at least one positionselected from the group consisting of Ser 532, Tyr 529, Tyr 451, Ile450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relative to SEQ IDNO:1.
 10. The compound of claim 9, wherein PROTEIN-Z-DOMAIN comprisesSEQ ID NO:16, SEQ ID NO:18, SEQ ID NO:20, (SEQ ID NO:24)-Z-(SEQ IDNO:26), or a mutant thereof comprising at least one mutation in at leastone position selected from the group consisting of Ser 532, Tyr 529, Tyr451, Ile 450, Ser 381, Tyr 382, Ser 377, Phe 346, Gly 531, Ser 289, Ser287, Ala 454, Gly 452, Gln 519, Glu 526, Lys 448, Glu 508, Arg 456, Asp276, Tyr 434, Gln 519, Ser 525, Gly 342, Ser 343 and Gly 536, relativeto SEQ ID NO:1.
 11. The compound of claim 1, wherein DOMAIN is an ALB orfragment thereof, and wherein PROTEIN-Z-DOMAIN comprises (SEQ IDNO:15)-Z-(ALB or fragment thereof), (SEQ ID NO:17)-Z-(ALB or fragmentthereof), (SEQ ID NO:19)-Z-(ALB or fragment thereof), (SEQ IDNO:24)-Z-(ALB or fragment thereof), or a mutant thereof comprising atleast one mutation in at least one position selected from the groupconsisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr 382, Ser377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln 519, Glu526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser 525, Gly342, Ser 343 and Gly 536, relative to SEQ ID NO:1.
 12. The compound ofclaim 11, wherein PROTEIN-Z-DOMAIN comprises SEQ ID NO:21, (SEQ IDN:17)-Z-(SEQ ID NO:27), SEQ ID NO:22, SEQ ID NO:25, or a mutant thereofcomprising at least one mutation in at least one position selected fromthe group consisting of Ser 532, Tyr 529, Tyr 451, Ile 450, Ser 381, Tyr382, Ser 377, Phe 346, Gly 531, Ser 289, Ser 287, Ala 454, Gly 452, Gln519, Glu 526, Lys 448, Glu 508, Arg 456, Asp 276, Tyr 434, Gln 519, Ser525, Gly 342, Ser 343 and Gly 536, relative to SEQ ID NO:1.
 13. Thecompound of claim 1, which has a k_(cat) value greater than or equal to3.4 (±0.4) s⁻¹ enzyme⁻¹, wherein the k_(cat) is determined by measuringthe compound's ATP hydrolysis rate.
 14. The compound of claim 1, whichhas a K_(M) value less than or equal to 2 μM, wherein the K_(M) isdetermined by measuring the compound's ATP hydrolysis rate.
 15. A methodof treating or preventing a disease or disorder associated withpathological calcification or pathological ossification in a subject inneed thereof, the method comprising administering to the subject atherapeutically effective amount of at least one compound of claim 1,wherein the disease comprises at least one selected from the groupconsisting of Generalized Arterial Calcification of Infancy (GACI),Idiopathic Infantile Arterial Calcification (IIAC), Ossification of thePosterior Longitudinal Ligament (OPLL), hypophosphatemic rickets,osteoarthritis, and calcification of atherosclerotic plaques.
 16. Themethod of claim 15, wherein Y is absent and the compound lacks anegatively-charged bone-targeting sequence.
 17. A method of treating orpreventing a disease or disorder associated with pathologicalcalcification or pathological ossification in a subject in need thereof,the method comprising administering to the subject a therapeuticallyeffective amount of at least one at least one compound of claim 1,wherein the disease comprises at least one selected from the groupconsisting of PXE, hereditary and non-hereditary forms ofosteoarthritis, ankylosing spondylitis, hardening of the arteriesoccurring with aging, calciphylaxis resulting from end stage renaldisease and progeria.
 18. The method of claim 17, wherein Y is absentand the compound lacks a negatively-charged bone-targeting sequence. 19.A method of reducing or preventing cardiac calcifications, arterialcalcifications or elastic fiber mineralizations in an infant afflictedwith at least one disease or disorder selected from the group consistingof GACI and PXE, the method comprising administering to the infant atherapeutically effective amount of a given polypeptide comprising anecto-nucleotide pyrophosphate/phosphodiesterase-1 (NPP1) polypeptide andan Fc, wherein the given polypeptide lacks a polyaspartic acid domain,whereby the administering of the given polypeptide increasesextracellular pyrophosphate (PPi) concentrations in the infant, thusreducing or preventing cardiac calcifications, arterial calcificationsor elastic fiber mineralization in the infant.
 20. The method of claim19, wherein the administering is subcutaneous.
 21. The method of claim19, wherein the administering restores the infant's extracellularpyrophosphate concentrations to a level within the range found in aninfant not afflicted with GACI or PXE.
 22. The method of claim 19,wherein the infant presents or is diagnosed with “failure to thrive”prior to the administering.
 23. The method of claim 19, wherein the NPP1polypeptide is a cleavage product of a precursor NPP1 polypeptidecomprising an ecto-nucleotide pyrophosphate/phosphodiesterase-2 (NPP2)transmembrane domain.
 24. The method of claim 19, wherein the NPP2transmembrane domain is residues 12-30 of NCBI accession no.NP_001124335 (SEQ ID NO:2), which corresponds to SEQ ID NO:23.
 25. Amethod of reducing or preventing cardiac calcifications, arterialcalcifications or elastic fiber mineralizations in an infant afflictedwith at least one disease or disorder selected from the group consistingof GACI and PXE, the method comprising administering to the infant atherapeutically effective amount of a given polypeptide comprising aNPP1 polypeptide and an ALB, wherein the given polypeptide lacks apolyaspartic acid domain, wherein the administering increasesextracellular PPi concentrations in the infant, thus reducing orpreventing cardiac calcifications, arterial calcifications or elasticfiber mineralization in the infant.
 26. The method of claim 25, whereinthe administering comprises subcutaneous administration.
 27. The methodof claim 25, wherein the administering restores the infant'sextracellular pyrophosphate concentrations to a level within the rangefound in an infant not afflicted with GACI or PXE.
 28. The method ofclaim 25, wherein the infant presents or is diagnosed with “failure tothrive” prior to the administering.